Who owns ATROB (ATROB)
Which tracked institutional funds hold ATROB, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See ATROB 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
113 tracked funds added or opened ATROB while 44 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
ATROB’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 ATROB more heavily than its largest holder by dollar value does.
Book-share is each fund’s reported value in ATROB 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 293 tracked filers holding ATROB, 162 increased or opened the position and 133 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 ATROB 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 23
- VANGUARD CAPITAL MANAGEMENT LLC$93M
- Pertento Partners LLP$54M
- Capital World Investors$37M
- VANGUARD PORTFOLIO MANAGEMENT LLC$24M
- JUPITER ASSET MANAGEMENT LTD$19M
- VANGUARD FIDUCIARY TRUST CO$15M
Full exits 12
- VANGUARD GROUP INC$93M
- ACK Asset Management LLC$32M
- SG Capital Management LLC$16M
- Atom Investors LP$10M
- Candelo Capital Management LP$5M
- 325 CAPITAL LLC$4M
Largest adds
- STATE STREET CORP$57M
- BlackRock, Inc.$37M
- AMERICAN CENTURY COMPANIES INC$20M
- Fisher Asset Management, LLC$20M
- GEODE CAPITAL MANAGEMENT, LLC$18M
- EMERALD ADVISERS, LLC$17M
Largest trims
- Luxor Capital Group, LP$24M
- Senator Investment Group LP$23M
- Driehaus Capital Management LLC$14M
- Capital International Investors$14M
- CITADEL ADVISORS LLC$11M
- Private Capital Management, LLC$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 |
|---|---|---|---|---|
| BlackRock, Inc. added | 2,825,410 | $189M | 8.8% | 2026-Q1 |
| STATE STREET CORP added | 2,349,815 | $157M | 7.3% | 2026-Q1 |
| AMERICAN CENTURY COMPANIES INC trimmed | 1,737,573 | $116M | 5.4% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 1,388,899 | $93M | 4.3% | 2026-Q1 |
| Capital International Investors trimmed | 1,288,947 | $86M | 4.0% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 887,033 | $59M | 2.8% | 2026-Q1 |
| Pertento Partners LLP new | 815,333 | $54M | 2.5% | 2026-Q1 |
| NEXT CENTURY GROWTH INVESTORS LLC trimmed | 786,317 | $52M | 2.5% | 2026-Q1 |
| DIMENSIONAL FUND ADVISORS LP added | 673,760 | $45M | 2.1% | 2026-Q1 |
| D. E. Shaw & Co., Inc. added | 608,449 | $41M | 1.9% | 2026-Q1 |
| Point72 Asset Management, L.P. added | 567,240 | $38M | 1.8% | 2026-Q1 |
| Capital World Investors new | 560,939 | $37M | 1.8% | 2026-Q1 |
| RAYMOND JAMES FINANCIAL INC added | 492,812 | $31M | 1.5% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC added | 455,054 | $30M | 1.4% | 2026-Q1 |
| AMERIPRISE FINANCIAL INC added | 450,667 | $30M | 1.4% | 2026-Q1 |
| EMERALD ADVISERS, LLC added | 449,126 | $30M | 1.4% | 2026-Q1 |
| MORGAN STANLEY trimmed | 447,541 | $30M | 1.4% | 2026-Q1 |
| Nuveen, LLC trimmed | 401,264 | $27M | 1.3% | 2026-Q1 |
| HENNESSY ADVISORS INC trimmed | 377,800 | $25M | 1.2% | 2026-Q1 |
| BNP PARIBAS FINANCIAL MARKETS trimmed | 371,030 | $25M | 1.2% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 366,014 | $24M | 1.1% | 2026-Q1 |
| ROYCE & ASSOCIATES LP trimmed | 363,383 | $24M | 1.1% | 2026-Q1 |
| Fisher Asset Management, LLC added | 348,842 | $23M | 1.1% | 2026-Q1 |
| Driehaus Capital Management LLC trimmed | 326,471 | $22M | 1.0% | 2026-Q1 |
| FRED ALGER MANAGEMENT, LLC added | 324,954 | $22M | 1.0% | 2026-Q1 |
| Private Capital Management, LLC trimmed | 322,543 | $22M | 1.0% | 2026-Q1 |
| UBS Group AG added | 291,144 | $19M | 0.9% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed | 288,762 | $19M | 0.9% | 2026-Q1 |
| JUPITER ASSET MANAGEMENT LTD new | 280,976 | $19M | 0.9% | 2026-Q1 |
| EMERALD MUTUAL FUND ADVISERS TRUST added | 279,159 | $19M | 0.9% | 2026-Q1 |
| NEEDHAM INVESTMENT MANAGEMENT LLC | 272,500 | $18M | 0.9% | 2026-Q1 |
| NORTHERN TRUST CORP added | 268,910 | $18M | 0.8% | 2026-Q1 |
| CASPIAN CAPITAL LP added | 267,724 | $18M | 0.8% | 2026-Q1 |
| DEUTSCHE BANK AG\ trimmed | 261,555 | $17M | 0.8% | 2026-Q1 |
| FIRST TRUST ADVISORS LP added | 253,492 | $17M | 0.8% | 2026-Q1 |
| MARSHALL WACE, LLP trimmed | 248,986 | $17M | 0.8% | 2026-Q1 |
| AQR CAPITAL MANAGEMENT LLC trimmed | 245,652 | $16M | 0.8% | 2026-Q1 |
| ACADIAN ASSET MANAGEMENT LLC added | 229,285 | $15M | 0.7% | 2026-Q1 |
| RENAISSANCE TECHNOLOGIES LLC added | 222,920 | $15M | 0.7% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC trimmed | 220,023 | $15M | 0.7% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 217,931 | $15M | 0.7% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP added | 216,727 | $14M | 0.7% | 2026-Q1 |
| CANADA PENSION PLAN INVESTMENT BOARD trimmed | 212,800 | $14M | 0.7% | 2026-Q1 |
| JANE STREET GROUP, LLC added | 201,091 | $13M | 0.6% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 199,722 | $13M | 0.6% | 2026-Q1 |
| M&G PLC new | 198,707 | $13M | 0.6% | 2026-Q1 |
| First Eagle Investment Management, LLC trimmed | 192,326 | $13M | 0.6% | 2026-Q1 |
| ROYAL BANK OF CANADA trimmed | 183,464 | $12M | 0.6% | 2026-Q1 |
| Congruence Capital, LLC trimmed | 175,366 | $12M | 0.5% | 2026-Q1 |
| Qube Research & Technologies Ltd added | 166,759 | $11M | 0.5% | 2026-Q1 |
| Invesco Ltd. trimmed | 159,573 | $11M | 0.5% | 2026-Q1 |
| KENNEDY CAPITAL MANAGEMENT LLC added | 143,717 | $10M | 0.4% | 2026-Q1 |
| Connor, Clark & Lunn Investment Management Ltd. trimmed | 142,499 | $10M | 0.4% | 2026-Q1 |
| HSBC HOLDINGS PLC trimmed | 144,233 | $9M | 0.4% | 2026-Q1 |
| Trexquant Investment LP added | 138,037 | $9M | 0.4% | 2026-Q1 |
| Advisors Asset Management, Inc. trimmed | 135,131 | $9M | 0.4% | 2026-Q1 |
| WELLS FARGO & COMPANY/MN added | 120,649 | $8M | 0.4% | 2026-Q1 |
| Bank of New York Mellon Corp trimmed | 115,298 | $8M | 0.4% | 2026-Q1 |
| PEREGRINE CAPITAL MANAGEMENT LLC new | 113,520 | $8M | 0.4% | 2026-Q1 |
| Walleye Capital LLC added | 110,412 | $7M | 0.3% | 2026-Q1 |
| VOLORIDGE INVESTMENT MANAGEMENT, LLC trimmed | 102,228 | $7M | 0.3% | 2026-Q1 |
| RBF Capital, LLC | 100,372 | $7M | 0.3% | 2026-Q1 |
| Hudson Bay Capital Management LP | 100,000 | $7M | 0.3% | 2026-Q1 |
| Informed Momentum Co LLC trimmed | 99,453 | $7M | 0.3% | 2026-Q1 |
| CITADEL ADVISORS LLC trimmed | 96,424 | $6M | 0.3% | 2026-Q1 |
| TORONTO DOMINION BANK trimmed | 94,375 | $6M | 0.3% | 2026-Q1 |
| FRANKLIN RESOURCES INC added | 89,010 | $6M | 0.3% | 2026-Q1 |
| ALGERT GLOBAL LLC added | 86,968 | $6M | 0.3% | 2026-Q1 |
| HRT FINANCIAL LP added | 78,376 | $5M | 0.2% | 2026-Q1 |
| PRINCIPAL FINANCIAL GROUP INC added | 76,475 | $5M | 0.2% | 2026-Q1 |
| PRUDENTIAL FINANCIAL INC trimmed | 75,445 | $5M | 0.2% | 2026-Q1 |
| NORDEA INVESTMENT MANAGEMENT AB trimmed | 75,230 | $5M | 0.2% | 2026-Q1 |
| LPL Financial LLC added | 72,914 | $5M | 0.2% | 2026-Q1 |
| NEW YORK STATE COMMON RETIREMENT FUND trimmed | 72,189 | $5M | 0.2% | 2026-Q1 |
| SEI INVESTMENTS CO added | 71,039 | $5M | 0.2% | 2026-Q1 |
| Minerva Advisors LLC trimmed | 70,340 | $5M | 0.2% | 2026-Q1 |
| Hennion & Walsh Asset Management, Inc. added | 66,076 | $4M | 0.2% | 2026-Q1 |
| Legal & General Group Plc trimmed | 63,343 | $4M | 0.2% | 2026-Q1 |
| Russell Investments Group, Ltd. added | 60,455 | $4M | 0.2% | 2026-Q1 |
| TUDOR INVESTMENT CORP ET AL trimmed | 58,966 | $4M | 0.2% | 2026-Q1 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP added | 57,898 | $4M | 0.2% | 2026-Q1 |
| BARCLAYS PLC added | 57,521 | $4M | 0.2% | 2026-Q1 |
| Teton Advisors, LLC trimmed | 57,000 | $4M | 0.2% | 2026-Q1 |
| JPMORGAN CHASE & CO added | 60,917 | $4M | 0.2% | 2026-Q1 |
| RHUMBLINE ADVISERS trimmed | 55,395 | $4M | 0.2% | 2026-Q1 |
| CAXTON ASSOCIATES LLP added | 55,334 | $4M | 0.2% | 2026-Q1 |
| Swiss National Bank | 52,100 | $3M | 0.2% | 2026-Q1 |
| STATE OF WISCONSIN INVESTMENT BOARD trimmed | 51,608 | $3M | 0.2% | 2026-Q1 |
| PDT Partners, LLC trimmed | 49,208 | $3M | 0.2% | 2026-Q1 |
| VANGUARD GROUP INC trimmed | 1,723,009 | $93M | 4.4% | 2025-Q4 stale |
| ACK Asset Management LLC trimmed | 597,469 | $32M | 1.5% | 2025-Q4 stale |
| DENDUR CAPITAL LP new | 362,000 | $17M | 0.8% | 2025-Q3 stale |
| SG Capital Management LLC added | 291,349 | $16M | 0.7% | 2025-Q4 stale |
| LAZARD ASSET MANAGEMENT LLC added | 236,140 | $11M | 0.5% | 2025-Q3 stale |
| Atom Investors LP new | 188,492 | $10M | 0.5% | 2025-Q4 stale |
| REDWOOD CAPITAL MANAGEMENT, LLC trimmed | 225,893 | $5M | 0.3% | 2025-Q1 stale |
| Candelo Capital Management LP new | 83,642 | $5M | 0.2% | 2025-Q4 stale |
| Teton Advisors, Inc. trimmed | 117,000 | $4M | 0.2% | 2025-Q2 stale |
| 325 CAPITAL LLC trimmed | 70,000 | $4M | 0.2% | 2025-Q4 stale |
| Squarepoint Ops LLC trimmed | 63,882 | $3M | 0.2% | 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.