Who owns Perma-Fix Environmental Services, Inc. (PESI)
Which tracked institutional funds hold PESI, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See PESI company fundamentals →
Ownership as of the 2026-Q1 13F filings. 13F is disclosed up to 45 days after quarter-end, so the most recent quarter fills in over the following weeks.
How the tape is positioned
8 tracked funds added or opened PESI while 20 trimmed or exited it between 2025-Q4 and 2026-Q1 — the tape is split. When large holders disagree on a name, the funds moving first are sometimes ahead of the story.
A prompt to read the filings, not a verdict. 13F is a quarter-end snapshot disclosed up to 45 days late; a fund adds or exits for mandate, benchmark, and timing reasons that have nothing to do with a view on the stock. This is a starting question, not a signal to trade.
Conviction spread
PESI’s largest tracked holder by dollar value, BlackRock, Inc., sizes it at 0.0% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 0.0pp gap the other way — the median holder sizes PESI more heavily than its largest holder by dollar value does.
Book-share is each fund’s reported value in PESI divided by its whole reported 13F book, so it is comparable across funds of different sizes and is unaffected by stock splits. A higher share means a fund has committed more of its book to the name — a starting question about conviction, not a verdict or a signal to trade.
Institutional & insider positioning
Between 2025-Q4 and 2026-Q1, across 85 tracked filers holding PESI, 37 increased or opened the position and 42 reduced or closed it; over the same quarter, there were no open-market insider Form 4s.
This fuses two public signals for the same quarter — how tracked institutions changed their positions and whether insiders bought or sold in the open market. It describes what was filed; it is a starting question, not a verdict or a signal to trade.
New buyers & exits
Funds opening or closing a position in PESI between the 2025-Q4 and 2026-Q1 13F filings, and the largest changes among funds holding it in both. New buyers and exits are counted on fund presence (split-invariant); adds and trims are measured on reported value.
New buyers 3
- VANGUARD CAPITAL MANAGEMENT LLC$8M
- VANGUARD FIDUCIARY TRUST CO$1M
- VANGUARD PORTFOLIO MANAGEMENT LLC$1M
Full exits 4
- VANGUARD GROUP INC$12M
- Perritt Capital Management Inc$2M
- Informed Momentum Co LLC$816K
- Ancora Advisors LLC$729K
Largest adds
- GROUP ONE TRADING LLC$3M
- North Star Investment Management Corp.$1M
- GOLDMAN SACHS GROUP INC$620K
- UBS Group AG$299K
- CITADEL ADVISORS LLC$286K
Largest trims
- BlackRock, Inc.$3M
- Rothschild Wealth LLC$2M
- MAK CAPITAL ONE LLC$2M
- JANE STREET GROUP, LLC$2M
- Prescott Group Capital Management, L.L.C.$1M
- Potomac Capital Management, Inc.$1M
Institutional holders
One row per tracked fund, largest reported value first. “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding. Rows marked stale are from an earlier filing than the security’s latest quarter — that fund is absent from the newest snapshot (position exited, or reported under a different name).
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| BlackRock, Inc. trimmed | 1,170,303 | $13M | 11.6% | 2026-Q1 |
| MAK CAPITAL ONE LLC | 918,673 | $10M | 9.1% | 2026-Q1 |
| Prescott Group Capital Management, L.L.C. | 777,142 | $8M | 7.7% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 759,435 | $8M | 7.5% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 432,701 | $5M | 4.3% | 2026-Q1 |
| HEARTLAND ADVISORS INC | 400,000 | $4M | 4.0% | 2026-Q1 |
| DIAMOND HILL CAPITAL MANAGEMENT INC trimmed | 355,978 | $4M | 3.5% | 2026-Q1 |
| STATE STREET CORP added | 335,547 | $4M | 3.3% | 2026-Q1 |
| Potomac Capital Management, Inc. trimmed | 296,700 | $3M | 2.9% | 2026-Q1 |
| GROUP ONE TRADING LLC added | 247,674 | $3M | 2.4% | 2026-Q1 |
| DIMENSIONAL FUND ADVISORS LP trimmed | 163,787 | $2M | 1.6% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC added | 142,687 | $2M | 1.4% | 2026-Q1 |
| NORTHERN TRUST CORP added | 129,568 | $1M | 1.3% | 2026-Q1 |
| North Star Investment Management Corp. added | 120,532 | $1M | 1.2% | 2026-Q1 |
| MYDA Advisors LLC added | 120,000 | $1M | 1.2% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 119,253 | $1M | 1.2% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 100,318 | $1M | 1.0% | 2026-Q1 |
| CITADEL ADVISORS LLC added | 69,313 | $741K | 0.7% | 2026-Q1 |
| D. E. Shaw & Co., Inc. trimmed | 62,989 | $673K | 0.6% | 2026-Q1 |
| UBS Group AG added | 62,082 | $664K | 0.6% | 2026-Q1 |
| Squarepoint Ops LLC added | 51,940 | $555K | 0.5% | 2026-Q1 |
| Pale Fire Capital SE added | 48,626 | $520K | 0.5% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 45,190 | $483K | 0.4% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed | 43,590 | $466K | 0.4% | 2026-Q1 |
| Bank of New York Mellon Corp trimmed | 40,379 | $432K | 0.4% | 2026-Q1 |
| CORSAIR CAPITAL MANAGEMENT, L.P. added | 37,649 | $402K | 0.4% | 2026-Q1 |
| SIMPLEX TRADING, LLC added | 31,318 | $335K | 0.3% | 2026-Q1 |
| GatePass Capital, LLC trimmed | 29,742 | $318K | 0.3% | 2026-Q1 |
| JANE STREET GROUP, LLC trimmed | 28,525 | $305K | 0.3% | 2026-Q1 |
| MORGAN STANLEY trimmed | 26,718 | $286K | 0.3% | 2026-Q1 |
| XTX Topco Ltd added | 23,227 | $248K | 0.2% | 2026-Q1 |
| Nuveen, LLC | 22,454 | $240K | 0.2% | 2026-Q1 |
| RHUMBLINE ADVISERS trimmed | 21,410 | $229K | 0.2% | 2026-Q1 |
| WELLS FARGO & COMPANY/MN trimmed | 20,830 | $223K | 0.2% | 2026-Q1 |
| Rothschild Wealth LLC trimmed | 20,600 | $220K | 0.2% | 2026-Q1 |
| BROWN ADVISORY INC new | 20,000 | $214K | 0.2% | 2026-Q1 |
| GUIDANCE CAPITAL, INC trimmed | 16,302 | $211K | 0.2% | 2026-Q1 |
| BAILARD, INC. | 17,800 | $190K | 0.2% | 2026-Q1 |
| Oxler Private Wealth LLC | 17,005 | $182K | 0.2% | 2026-Q1 |
| IMC-Chicago, LLC new | 16,933 | $181K | 0.2% | 2026-Q1 |
| Quent Capital, LLC | 16,199 | $173K | 0.2% | 2026-Q1 |
| GSA CAPITAL PARTNERS LLP new | 16,097 | $172K | 0.2% | 2026-Q1 |
| OSAIC HOLDINGS, INC. added | 16,000 | $171K | 0.2% | 2026-Q1 |
| DEUTSCHE BANK AG\ added | 14,621 | $156K | 0.1% | 2026-Q1 |
| Fermata Advisors, LLC added | 12,936 | $138K | 0.1% | 2026-Q1 |
| Greenhaven Road Investment Management, L.P. added | 11,303 | $120K | 0.1% | 2026-Q1 |
| PRICE T ROWE ASSOCIATES INC /MD/ | 11,202 | $120K | 0.1% | 2026-Q1 |
| Invesco Ltd. trimmed | 11,135 | $119K | 0.1% | 2026-Q1 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP trimmed | 11,098 | $119K | 0.1% | 2026-Q1 |
| AMERICAN CENTURY COMPANIES INC new | 10,692 | $114K | 0.1% | 2026-Q1 |
| Vident Advisory, LLC new | 10,390 | $111K | 0.1% | 2026-Q1 |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. added | 8,223 | $88K | 0.1% | 2026-Q1 |
| JPMORGAN CHASE & CO trimmed | 7,082 | $74K | 0.1% | 2026-Q1 |
| Vanguard Global Advisers, LLC new | 5,742 | $61K | 0.1% | 2026-Q1 |
| Police & Firemen's Retirement System of New Jersey | 5,649 | $60K | 0.1% | 2026-Q1 |
| Capital Advisors, Ltd. LLC new | 5,000 | $53K | 0.0% | 2026-Q1 |
| MetLife Investment Management, LLC trimmed | 4,922 | $53K | 0.0% | 2026-Q1 |
| FMR LLC trimmed | 4,726 | $51K | 0.0% | 2026-Q1 |
| NEW YORK STATE COMMON RETIREMENT FUND | 4,400 | $47K | 0.0% | 2026-Q1 |
| BNP PARIBAS FINANCIAL MARKETS trimmed | 3,669 | $39K | 0.0% | 2026-Q1 |
| BARCLAYS PLC trimmed | 3,273 | $35K | 0.0% | 2026-Q1 |
| Russell Investments Group, Ltd. added | 1,732 | $19K | 0.0% | 2026-Q1 |
| Legal & General Group Plc trimmed | 1,558 | $17K | 0.0% | 2026-Q1 |
| Tower Research Capital LLC (TRC) trimmed | 1,528 | $16K | 0.0% | 2026-Q1 |
| Ameritas Investment Partners, Inc. | 1,232 | $13K | 0.0% | 2026-Q1 |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM trimmed | 936 | $10K | 0.0% | 2026-Q1 |
| CITIGROUP INC added | 819 | $9K | 0.0% | 2026-Q1 |
| Sterling Capital Management LLC trimmed | 501 | $5K | 0.0% | 2026-Q1 |
| VANGUARD GROUP INC added | 968,107 | $12M | 11.3% | 2025-Q4 stale |
| VAN ECK ASSOCIATES CORP added | 220,289 | $2M | 2.1% | 2025-Q3 stale |
| Perritt Capital Management Inc trimmed | 166,300 | $2M | 1.9% | 2025-Q4 stale |
| ESSEX INVESTMENT MANAGEMENT CO LLC added | 196,197 | $2M | 1.8% | 2025-Q3 stale |
| Alyeska Investment Group, L.P. trimmed | 147,417 | $1M | 1.0% | 2025-Q1 stale |
| Informed Momentum Co LLC trimmed | 64,784 | $816K | 0.8% | 2025-Q4 stale |
| THOMPSON SIEGEL & WALMSLEY LLC trimmed | 104,778 | $762K | 0.7% | 2025-Q1 stale |
| Ancora Advisors LLC trimmed | 57,927 | $729K | 0.7% | 2025-Q4 stale |
| Legato Capital Management LLC | 56,459 | $570K | 0.5% | 2025-Q3 stale |
| SEI INVESTMENTS CO new | 39,442 | $497K | 0.5% | 2025-Q4 stale |
| MILLENNIUM MANAGEMENT LLC added | 38,617 | $486K | 0.4% | 2025-Q4 stale |
| ARS Investment Partners, LLC trimmed | 36,145 | $455K | 0.4% | 2025-Q4 stale |
| Trexquant Investment LP added | 42,156 | $426K | 0.4% | 2025-Q3 stale |
| LOS ANGELES CAPITAL MANAGEMENT LLC new | 22,960 | $322K | 0.3% | 2025-Q4 stale |
| CW Advisors, LLC added | 30,500 | $321K | 0.3% | 2025-Q2 stale |
| COMMONS CAPITAL, LLC | 30,350 | $319K | 0.3% | 2025-Q2 stale |
| MOODY NATIONAL BANK TRUST DIVISION | 25,000 | $263K | 0.2% | 2025-Q2 stale |
| Brookwood Investment Group LLC added | 20,873 | $263K | 0.2% | 2025-Q4 stale |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC | 20,300 | $214K | 0.2% | 2025-Q2 stale |
| BLUE SQUARE ASSET MANAGEMENT, LLC new | 20,100 | $203K | 0.2% | 2025-Q3 stale |
| MARSHALL WACE, LLP added | 18,405 | $194K | 0.2% | 2025-Q2 stale |
| HRT FINANCIAL LP trimmed | 14,585 | $183K | 0.2% | 2025-Q4 stale |
| Verition Fund Management LLC new | 14,456 | $146K | 0.1% | 2025-Q3 stale |
| THOMPSON DAVIS & CO., INC. trimmed | 13,440 | $98K | 0.1% | 2025-Q1 stale |
| RENAISSANCE TECHNOLOGIES LLC trimmed | 11,474 | $83K | 0.1% | 2025-Q1 stale |
| OPPENHEIMER & CO INC trimmed | 10,950 | $80K | 0.1% | 2025-Q1 stale |
| Cubist Systematic Strategies, LLC trimmed | 10,569 | $77K | 0.1% | 2025-Q1 stale |
| Corebridge Financial, Inc. added | 8,284 | $60K | 0.1% | 2025-Q1 stale |
| RAYMOND JAMES FINANCIAL INC new | 1,160 | $12K | 0.0% | 2025-Q2 stale |
| FLAGSHIP HARBOR ADVISORS, LLC new | 910 | $11K | 0.0% | 2025-Q4 stale |
| AMALGAMATED BANK trimmed | 544 | $7K | 0.0% | 2025-Q4 stale |
| Global Retirement Partners, LLC new | 500 | $6K | 0.0% | 2025-Q4 stale |
Ownership over time
Tracked institutional holder count and total shares held by filing quarter (independent scales). The curated-era tail and any mid-ingest latest quarter are handled honestly — a partial quarter is not drawn as a collapse.
Reading this table
Funds hold the same stock for different reasons — an index fund “holds” almost everything, an active manager sizes a name to a mandate and a benchmark, and each fund entered at its own price and time. Because 13F is filed up to 45 days after quarter-end, every row is a backward-looking snapshot; a manager may have traded since. Share-class siblings (a company’s A and C shares) are rolled up to one line so a dual-class name is never double-counted. Compare like-for-like. A large holder is not an endorsement, and a fund exiting is not a warning — this is a starting question, not a verdict.
About 13F filings
A Form 13F is a quarterly disclosure that institutional investment managers with over $100 million in US-listed equities must file with the SEC. In plain English: it is a snapshot of the long stock positions a fund held at the end of a quarter. It covers long US-listed equities only — not short positions, options, cash, or private holdings — and the funds shown are the large sample we track, not the complete 13F universe.