Who owns ATKR (ATKR)
Which tracked institutional funds hold ATKR, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See ATKR 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
58 tracked funds added or opened ATKR while 86 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
ATKR’s largest tracked holder by dollar value, VANGUARD GROUP 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 ATKR more heavily than its largest holder by dollar value does.
Book-share is each fund’s reported value in ATKR 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 304 tracked filers holding ATKR, 155 increased or opened the position and 150 reduced or closed it; over the same quarter, open-market insider Form 4 buying and selling roughly offset.
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 ATKR 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 22
- VANGUARD PORTFOLIO MANAGEMENT LLC$123M
- VANGUARD CAPITAL MANAGEMENT LLC$89M
- Oslo Pensjonsforsikring AS$22M
- CANYON CAPITAL ADVISORS LLC$18M
- VANGUARD FIDUCIARY TRUST CO$13M
- Woodline Partners LP$6M
Full exits 24
- VANGUARD GROUP INC$212M
- ADAGE CAPITAL PARTNERS GP, L.L.C.$19M
- WELLINGTON MANAGEMENT GROUP LLP$12M
- ExodusPoint Capital Management, LP$8M
- COMMONWEALTH OF PENNSYLVANIA PUBLIC SCHOOL EMPLS RETRMT SYS$6M
- North Growth Management Ltd.$6M
Largest adds
- MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd.$9M
- TWO SIGMA INVESTMENTS, LP$7M
- PDT Partners, LLC$7M
- AMERICAN CENTURY COMPANIES INC$5M
- BARCLAYS PLC$5M
- DEUTSCHE BANK AG\$5M
Largest trims
- Pacer Advisors, Inc.$21M
- FIRST TRUST ADVISORS LP$15M
- Gates Capital Management, Inc.$15M
- JPMORGAN CHASE & CO$11M
- JANE STREET GROUP, LLC$9M
- VICTORY CAPITAL MANAGEMENT INC$9M
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 |
|---|---|---|---|---|
| Gates Capital Management, Inc. trimmed | 2,685,718 | $158M | 7.3% | 2026-Q1 |
| BlackRock, Inc. added | 2,626,791 | $155M | 7.1% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 2,090,469 | $123M | 5.7% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 1,515,110 | $89M | 4.1% | 2026-Q1 |
| AMERICAN CENTURY COMPANIES INC added | 1,439,116 | $85M | 3.9% | 2026-Q1 |
| DIMENSIONAL FUND ADVISORS LP added | 1,227,991 | $72M | 3.3% | 2026-Q1 |
| FIRST TRUST ADVISORS LP trimmed | 1,226,840 | $72M | 3.3% | 2026-Q1 |
| LSV ASSET MANAGEMENT added | 1,051,861 | $62M | 2.8% | 2026-Q1 |
| Coliseum Capital Management, LLC added | 947,070 | $56M | 2.6% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 854,731 | $50M | 2.3% | 2026-Q1 |
| STATE STREET CORP added | 835,156 | $49M | 2.3% | 2026-Q1 |
| EARNEST PARTNERS LLC trimmed | 777,905 | $46M | 2.1% | 2026-Q1 |
| Hill City Capital, LP | 728,206 | $43M | 2.0% | 2026-Q1 |
| Harding Loevner LP trimmed | 704,862 | $42M | 1.9% | 2026-Q1 |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP trimmed | 698,134 | $41M | 1.9% | 2026-Q1 |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. added | 532,992 | $31M | 1.4% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 462,278 | $27M | 1.2% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC added | 417,644 | $25M | 1.1% | 2026-Q1 |
| GENDELL JEFFREY L added | 400,214 | $24M | 1.1% | 2026-Q1 |
| VICTORY CAPITAL MANAGEMENT INC trimmed | 379,274 | $22M | 1.0% | 2026-Q1 |
| LONDON CO OF VIRGINIA trimmed | 377,623 | $22M | 1.0% | 2026-Q1 |
| Oslo Pensjonsforsikring AS new | 377,000 | $22M | 1.0% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP added | 353,000 | $21M | 1.0% | 2026-Q1 |
| NEW YORK STATE COMMON RETIREMENT FUND trimmed | 343,515 | $20M | 0.9% | 2026-Q1 |
| JACOBS LEVY EQUITY MANAGEMENT, INC added | 343,289 | $20M | 0.9% | 2026-Q1 |
| MORGAN STANLEY trimmed | 338,300 | $20M | 0.9% | 2026-Q1 |
| NORTHERN TRUST CORP trimmed | 321,363 | $19M | 0.9% | 2026-Q1 |
| CANYON CAPITAL ADVISORS LLC new | 305,000 | $18M | 0.8% | 2026-Q1 |
| Swedbank AB | 296,206 | $17M | 0.8% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC trimmed | 276,092 | $16M | 0.7% | 2026-Q1 |
| CANADA PENSION PLAN INVESTMENT BOARD trimmed | 247,162 | $15M | 0.7% | 2026-Q1 |
| JPMORGAN CHASE & CO trimmed | 250,308 | $15M | 0.7% | 2026-Q1 |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC added | 244,183 | $14M | 0.7% | 2026-Q1 |
| Bank of New York Mellon Corp added | 235,919 | $14M | 0.6% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 218,268 | $13M | 0.6% | 2026-Q1 |
| SEI INVESTMENTS CO added | 208,454 | $12M | 0.6% | 2026-Q1 |
| Nuveen, LLC added | 193,913 | $11M | 0.5% | 2026-Q1 |
| WELLS FARGO & COMPANY/MN trimmed | 178,047 | $10M | 0.5% | 2026-Q1 |
| NORGES BANK added | 167,656 | $10M | 0.5% | 2026-Q1 |
| DNB Asset Management AS added | 166,582 | $10M | 0.5% | 2026-Q1 |
| FEDERATED HERMES, INC. added | 159,628 | $9M | 0.4% | 2026-Q1 |
| BARCLAYS PLC added | 158,793 | $9M | 0.4% | 2026-Q1 |
| DEUTSCHE BANK AG\ added | 156,118 | $9M | 0.4% | 2026-Q1 |
| HOTCHKIS & WILEY CAPITAL MANAGEMENT LLC trimmed | 153,486 | $9M | 0.4% | 2026-Q1 |
| Man Group plc added | 150,330 | $9M | 0.4% | 2026-Q1 |
| Qube Research & Technologies Ltd added | 147,045 | $9M | 0.4% | 2026-Q1 |
| Empowered Funds, LLC added | 133,516 | $8M | 0.4% | 2026-Q1 |
| HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND added | 125,800 | $7M | 0.3% | 2026-Q1 |
| Allianz Asset Management GmbH added | 121,937 | $7M | 0.3% | 2026-Q1 |
| PDT Partners, LLC added | 116,168 | $7M | 0.3% | 2026-Q1 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC added | 106,270 | $6M | 0.3% | 2026-Q1 |
| Woodline Partners LP new | 102,081 | $6M | 0.3% | 2026-Q1 |
| Invesco Ltd. trimmed | 94,349 | $6M | 0.3% | 2026-Q1 |
| Russell Investments Group, Ltd. added | 94,309 | $6M | 0.3% | 2026-Q1 |
| NORDEA INVESTMENT MANAGEMENT AB trimmed | 93,483 | $5M | 0.2% | 2026-Q1 |
| Rock Point Advisors, LLC added | 85,685 | $5M | 0.2% | 2026-Q1 |
| VOLORIDGE INVESTMENT MANAGEMENT, LLC trimmed | 85,587 | $5M | 0.2% | 2026-Q1 |
| Allspring Global Investments Holdings, LLC trimmed | 76,830 | $5M | 0.2% | 2026-Q1 |
| UBS Group AG added | 77,232 | $5M | 0.2% | 2026-Q1 |
| BNP PARIBAS FINANCIAL MARKETS added | 76,228 | $4M | 0.2% | 2026-Q1 |
| NOMURA ASSET MANAGEMENT INTERNATIONAL INC. added | 74,282 | $4M | 0.2% | 2026-Q1 |
| KESTREL INVESTMENT MANAGEMENT CORP trimmed | 74,150 | $4M | 0.2% | 2026-Q1 |
| Universal- Beteiligungs- und Servicegesellschaft mbH | 73,456 | $4M | 0.2% | 2026-Q1 |
| ENVESTNET ASSET MANAGEMENT INC added | 72,701 | $4M | 0.2% | 2026-Q1 |
| AMERIPRISE FINANCIAL INC trimmed | 70,514 | $4M | 0.2% | 2026-Q1 |
| MARTINGALE ASSET MANAGEMENT L P added | 69,738 | $4M | 0.2% | 2026-Q1 |
| Swiss National Bank | 66,400 | $4M | 0.2% | 2026-Q1 |
| CITADEL ADVISORS LLC trimmed | 64,743 | $4M | 0.2% | 2026-Q1 |
| PRUDENTIAL FINANCIAL INC added | 64,190 | $4M | 0.2% | 2026-Q1 |
| Allianz SE | 62,273 | $4M | 0.2% | 2026-Q1 |
| D. E. Shaw & Co., Inc. trimmed | 61,270 | $4M | 0.2% | 2026-Q1 |
| RAYMOND JAMES FINANCIAL INC added | 60,821 | $4M | 0.2% | 2026-Q1 |
| DENALI ADVISORS LLC | 55,000 | $3M | 0.1% | 2026-Q1 |
| EDENTREE ASSET MANAGEMENT Ltd | 54,550 | $3M | 0.1% | 2026-Q1 |
| AQR CAPITAL MANAGEMENT LLC added | 50,770 | $3M | 0.1% | 2026-Q1 |
| JANE STREET GROUP, LLC trimmed | 48,689 | $3M | 0.1% | 2026-Q1 |
| O'SHAUGHNESSY ASSET MANAGEMENT, LLC trimmed | 48,593 | $3M | 0.1% | 2026-Q1 |
| BALYASNY ASSET MANAGEMENT L.P. trimmed | 46,663 | $3M | 0.1% | 2026-Q1 |
| VANGUARD GROUP INC trimmed | 3,357,839 | $212M | 9.7% | 2025-Q4 stale |
| Orbis Allan Gray Ltd added | 364,011 | $26M | 1.2% | 2025-Q2 stale |
| River Road Asset Management, LLC trimmed | 336,274 | $21M | 1.0% | 2025-Q3 stale |
| Anomaly Capital Management, LP trimmed | 278,476 | $20M | 0.9% | 2025-Q2 stale |
| ADAGE CAPITAL PARTNERS GP, L.L.C. new | 297,000 | $19M | 0.9% | 2025-Q4 stale |
| WELLINGTON MANAGEMENT GROUP LLP trimmed | 188,262 | $12M | 0.5% | 2025-Q4 stale |
| ExodusPoint Capital Management, LP added | 124,624 | $8M | 0.4% | 2025-Q4 stale |
| PALISADE CAPITAL MANAGEMENT, LP trimmed | 103,464 | $7M | 0.3% | 2025-Q2 stale |
| Cambria Investment Management, L.P. added | 115,479 | $7M | 0.3% | 2025-Q3 stale |
| COMMONWEALTH OF PENNSYLVANIA PUBLIC SCHOOL EMPLS RETRMT SYS | 94,000 | $6M | 0.3% | 2025-Q4 stale |
| North Growth Management Ltd. added | 94,000 | $6M | 0.3% | 2025-Q4 stale |
| DECADE RENEWABLE PARTNERS LP trimmed | 69,678 | $5M | 0.2% | 2025-Q2 stale |
| TWO SIGMA ADVISERS, LP added | 67,300 | $4M | 0.2% | 2025-Q4 stale |
| THOMPSON SIEGEL & WALMSLEY LLC trimmed | 65,458 | $4M | 0.2% | 2025-Q4 stale |
| MACQUARIE GROUP LTD trimmed | 60,675 | $4M | 0.2% | 2025-Q3 stale |
| Lighthouse Investment Partners, LLC added | 60,822 | $4M | 0.2% | 2025-Q1 stale |
| PRINCIPAL FINANCIAL GROUP INC added | 58,174 | $3M | 0.2% | 2025-Q1 stale |
| ALGERT GLOBAL LLC added | 53,054 | $3M | 0.2% | 2025-Q3 stale |
| CacheTech Inc. added | 47,076 | $3M | 0.1% | 2025-Q4 stale |
| VAN DEN BERG MANAGEMENT I, INC trimmed | 42,196 | $3M | 0.1% | 2025-Q2 stale |
| MARSHALL WACE, LLP trimmed | 47,051 | $3M | 0.1% | 2025-Q4 stale |
| Ruffer LLP trimmed | 44,841 | $3M | 0.1% | 2025-Q3 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.