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Perma-Fix Environmental Services, Inc. (PESI) institutional ownership

Latest close $16.16 Jul 23, 2026
Market cap$302M 52-week range SectorIndustrials
Funds holding · Q1 2026
72
reported PESI position changes
Top owners · Q1 2026
No disclosed owners are available.
Institutional activity · Q1 2026
Activity unavailable N/A
34 buyers · 38 sellers

Perma-Fix Environmental Services, Inc. (PESI) price and institutional activity

Dates

Q1 2026

$0 bought by 34 investors
Group One Trading LLCNorth Star Investment Management Corp. +32 more
$0 sold by 38 investors
Rothschild Wealth LLCJane Street Group, LLC +36 more
Bought Sold Totals per quarter; hover a bar for the names.

Perma-Fix Environmental Services, Inc. (PESI) institutional activity · 72

Investor Type Est. change Change Δ Own Date
Group One Trading LLC · Added
Change +244K Date Q1 2026
Group One Trading LLC Added· Q1 2026 +244K Q1 2026
Rothschild Wealth LLC · Reduced
Change −146K Date Q1 2026
Rothschild Wealth LLC Reduced· Q1 2026 −146K Q1 2026
North Star Investment Management Corp. · Added
Change +116K Date Q1 2026
North Star Investment Management Corp. Added· Q1 2026 +116K Q1 2026
Jane Street Group, LLC · Reduced
Change −116K Date Q1 2026
Jane Street Group, LLC Reduced· Q1 2026 −116K Q1 2026
Susquehanna International Group, LLP · Reduced
Change −87K Date Q1 2026
Susquehanna International Group, LLP Reduced· Q1 2026 −87K Q1 2026
Goldman Sachs Group Inc · Added
Change +71K Date Q1 2026
Goldman Sachs Group Inc Added· Q1 2026 +71K Q1 2026
Informed Momentum Co LLC · Exited
Change −65K Δ Own −100.0% Date Q1 2026
Informed Momentum Co LLC Exited· Q1 2026 −65K −100.0% Q1 2026
Ancora Advisors LLC · Exited
Change −58K Δ Own −100.0% Date Q1 2026
Ancora Advisors LLC Exited· Q1 2026 −58K −100.0% Q1 2026
Potomac Capital Management, Inc. · Reduced
Change −45K Date Q1 2026
Potomac Capital Management, Inc. Reduced· Q1 2026 −45K Q1 2026
Morgan Stanley · Reduced
Change −40K Date Q1 2026
Morgan Stanley Reduced· Q1 2026 −40K Q1 2026
Millennium Management LLC · Exited
Change −39K Δ Own −100.0% Date Q1 2026
Millennium Management LLC Exited· Q1 2026 −39K −100.0% Q1 2026
Ars Investment Partners, LLC · Exited
Change −36K Δ Own −100.0% Date Q1 2026
Ars Investment Partners, LLC Exited· Q1 2026 −36K −100.0% Q1 2026
Gatepass Capital, LLC · Reduced
Change −35K Date Q1 2026
Gatepass Capital, LLC Reduced· Q1 2026 −35K Q1 2026
Citadel Advisors LLC Added· Q1 2026 +33K +91.8% Q1 2026
UBS Group AG · Added
Change +33K Date Q1 2026
UBS Group AG Added· Q1 2026 +33K Q1 2026
Data through Q1 2026 · filed Jun 2, 2026
15 of 72

Famous investor activity in Perma-Fix Environmental Services, Inc. (PESI)

Perma-Fix Environmental Services, Inc. (PESI) insider trading

Company insiders, action and economics first; trade and filed dates last.
Dates
Insider Title Type Price Qty Value Owned ΔOwn Trade date Filed date
Reeder Joe · Director Grant (A) 10K
Owned 10K Trade date Jul 22, 2026 Filed date Jul 24, 2026
Reeder Joe Director Grant (A) 10K 10K Jul 22, 2026 Jul 24, 2026
Wamp Zach Paul · Director Grant (A) 10K
Owned 10K Trade date Jul 22, 2026 Filed date Jul 23, 2026
Wamp Zach Paul Director Grant (A) 10K 10K Jul 22, 2026 Jul 23, 2026
Shelton Larry · Director Grant (A) 10K
Owned 10K Trade date Jul 22, 2026 Filed date Jul 23, 2026
Shelton Larry Director Grant (A) 10K 10K Jul 22, 2026 Jul 23, 2026
Zwecker Mark A. · Director Grant (A) 10K
Owned 10K Trade date Jul 22, 2026 Filed date Jul 23, 2026
Zwecker Mark A. Director Grant (A) 10K 10K Jul 22, 2026 Jul 23, 2026
Bostick Thomas · Director Grant (A) 10K
Owned 10K Trade date Jul 22, 2026 Filed date Jul 23, 2026
Bostick Thomas Director Grant (A) 10K 10K Jul 22, 2026 Jul 23, 2026
Grumski Joseph Timothy · Director Grant (A) 10K
Owned 10K Trade date Jul 22, 2026 Filed date Jul 23, 2026
Grumski Joseph Timothy Director Grant (A) 10K 10K Jul 22, 2026 Jul 23, 2026
Duggan Kerry C. · Director Grant (A) 10K
Owned 10K Trade date Jul 22, 2026 Filed date Jul 23, 2026
Duggan Kerry C. Director Grant (A) 10K 10K Jul 22, 2026 Jul 23, 2026
Shelton Larry · Director 2 operations 0
Price $4.60 Owned 0 Trade date Jul 13, 2026 Filed date Jul 14, 2026
Shelton Larry Director 2 operations $4.60 0 0 Jul 13, 2026 Jul 14, 2026
Grumski Joseph Timothy · Director Grant (A) $16K
Price $10.72 Qty 2K Owned 68K ΔOwn +2.3% Trade date Jul 1, 2026 Filed date Jul 2, 2026
Grumski Joseph Timothy Director Grant (A) $10.72 2K $16K 68K +2.3% Jul 1, 2026 Jul 2, 2026
Zwecker Mark A. · Director Grant (A) $13K
Price $10.72 Qty 1K Owned 248K ΔOwn +0.5% Trade date Jul 1, 2026 Filed date Jul 2, 2026
Zwecker Mark A. Director Grant (A) $10.72 1K $13K 248K +0.5% Jul 1, 2026 Jul 2, 2026
Bostick Thomas · Director Grant (A) $13K
Price $10.72 Qty 1K Owned 51K ΔOwn +2.5% Trade date Jul 1, 2026 Filed date Jul 2, 2026
Bostick Thomas Director Grant (A) $10.72 1K $13K 51K +2.5% Jul 1, 2026 Jul 2, 2026
Reeder Joe · Director Grant (A) $16K
Price $10.72 Qty 1K Owned 239K ΔOwn +0.6% Trade date Jul 1, 2026 Filed date Jul 2, 2026
Reeder Joe Director Grant (A) $10.72 1K $16K 239K +0.6% Jul 1, 2026 Jul 2, 2026
Wamp Zach Paul · Director Grant (A) $9K
Price $10.72 Qty 849 Owned 53K ΔOwn +1.6% Trade date Jul 1, 2026 Filed date Jul 2, 2026
Wamp Zach Paul Director Grant (A) $10.72 849 $9K 53K +1.6% Jul 1, 2026 Jul 2, 2026
Duggan Kerry C. · Director Grant (A) $9K
Price $10.72 Qty 819 Owned 8K ΔOwn +12.0% Trade date Jul 1, 2026 Filed date Jul 2, 2026
Duggan Kerry C. Director Grant (A) $10.72 819 $9K 8K +12.0% Jul 1, 2026 Jul 2, 2026
Shelton Larry · Director Grant (A) $15K
Price $10.72 Qty 1K Owned 197K ΔOwn +0.7% Trade date Jul 1, 2026 Filed date Jul 2, 2026
Shelton Larry Director Grant (A) $10.72 1K $15K 197K +0.7% Jul 1, 2026 Jul 2, 2026
15 of 46
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Perma-Fix Environmental Services, Inc. (PESI) activist and large shareholders

Dates
Owner/Filer identity Shares reported % of shares outstanding Filing date
Blackrock, Inc. 1.0M
% of shares outstanding 6.4% Filing date Nov 8, 2024
Blackrock, Inc. 1.0M 6.4% Nov 8, 2024
Heartland Advisors Inc 649K
% of shares outstanding 4.9% Filing date Apr 12, 2023
Heartland Advisors Inc 649K 4.9% Apr 12, 2023
2 of 2

Perma-Fix Environmental Services, Inc. (PESI) ownership FAQ

Who owns PESI?

72 reporting institutions disclosed PESI position changes in the Q1 2026 snapshot.

How is institutional activity calculated?

For each manager, WhoBought compares accepted consecutive 13F share counts. Share change is current shares minus prior shares. Estimated dollar change is that signed share change multiplied by the split-adjusted quarter-mean close. The activity table on this page uses Q1 2026.

What are activist and large shareholder filings?

An investor crossing 5% of a share class generally files Schedule 13D for activist intent or Schedule 13G for a passive position. The technical form names appear here rather than in the activity rows.

Where does this data come from?

Ownership and institutional activity come from SEC Form 13F filings. Insider activity comes from SEC Form 4, and large-shareholder activity from SEC Schedules 13D and 13G. FMP supplies price data only. Company logos use the local verified Parqet cache with one shared fallback.

Why are ownership reports delayed?

Form 13F is a quarterly disclosure and is normally filed after the quarter ends. Every ownership and activity value therefore names its represented period; it is not presented as a live position.

How are missing table values shown?

A muted dash marks a missing table value. It means the filing omitted the value, comparable data is unavailable, or no prior position exists for comparison.