Who owns ATI (ATI)
Which tracked institutional funds hold ATI, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See ATI company fundamentals →
Ownership as of the 2026-Q2 13F filings (latest filed 2026-09-22). 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
The tracked-fund tape on ATI is one-sided between 2026-Q1 and 2026-Q2: 362 added or opened and 98 trimmed or exited — on balance accumulating.
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
ATI’s largest tracked holder by dollar value, BlackRock, Inc., sizes it at 0.1% of its own reported 13F book, while the median holder sizes it at 0.1% of theirs — a 0.0pp gap the other way — the median holder sizes ATI more heavily than its largest holder by dollar value does.
Book-share is each fund’s reported value in ATI 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 2026-Q1 and 2026-Q2, across 748 tracked filers holding ATI, 458 increased or opened the position and 308 reduced or closed it; over the same quarter, open-market insider Form 4s were net sales.
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 ATI between the 2026-Q1 and 2026-Q2 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 55
- POLEN CAPITAL MANAGEMENT LLC$161M
- DSM CAPITAL PARTNERS LLC$87M
- Clearbridge Investments, LLC$55M
- Yaupon Capital Management LP$36M
- Oribel Capital Management, LP$19M
- KEYSTONE INVESTORS PTE LTD$18M
Full exits 49
- SG Americas Securities, LLC$156M
- Amundi$38M
- HRT FINANCIAL LP$37M
- LORD, ABBETT & CO. LLC$26M
- NEW YORK STATE TEACHERS RETIREMENT SYSTEM$20M
- NATIXIS ADVISORS, LLC$18M
Largest adds
- BlackRock, Inc.$1.7B
- VANGUARD PORTFOLIO MANAGEMENT LLC$379M
- VANGUARD CAPITAL MANAGEMENT LLC$324M
- Qube Research & Technologies Ltd$298M
- NORGES BANK$266M
- STATE STREET CORP$250M
Largest trims
- VIKING GLOBAL INVESTORS LP$257M
- Capital International Investors$122M
- UBS Group AG$115M
- PNC Financial Services Group, Inc.$114M
- D. E. Shaw & Co., Inc.$93M
- PRUDENTIAL FINANCIAL INC$82M
Institutional holders
One row per tracked fund, most shares held first (every row is from one quarter; reported value breaks ties). “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding.
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| BlackRock, Inc. added | 18,708,922 | $3.7B | 16.5% | 2026-Q2 |
| VANGUARD PORTFOLIO MANAGEMENT LLC added | 6,219,875 | $1.2B | 5.5% | 2026-Q2 |
| VANGUARD CAPITAL MANAGEMENT LLC added | 6,162,418 | $1.2B | 5.4% | 2026-Q2 |
| Capital World Investors trimmed | 5,249,249 | $1.0B | 4.6% | 2026-Q2 |
| STATE STREET CORP trimmed | 5,237,299 | $1.0B | 4.6% | 2026-Q2 |
| Capital Research Global Investors trimmed | 5,093,768 | $1.0B | 4.5% | 2026-Q2 |
| FMR LLC trimmed | 4,989,171 | $983M | 4.4% | 2026-Q2 |
| Capital International Investors trimmed | 3,719,485 | $733M | 3.3% | 2026-Q2 |
| Invesco Ltd. trimmed | 3,449,291 | $680M | 3.0% | 2026-Q2 |
| GEODE CAPITAL MANAGEMENT, LLC trimmed | 2,777,512 | $548M | 2.4% | 2026-Q2 |
| Qube Research & Technologies Ltd added | 2,144,028 | $423M | 1.9% | 2026-Q2 |
| MORGAN STANLEY added | 1,865,178 | $368M | 1.6% | 2026-Q2 |
| BANK OF AMERICA CORP /DE/ added | 1,767,047 | $348M | 1.6% | 2026-Q2 |
| NORGES BANK added | 1,739,884 | $343M | 1.5% | 2026-Q2 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed | 1,483,253 | $292M | 1.3% | 2026-Q2 |
| AQR CAPITAL MANAGEMENT LLC added | 1,432,935 | $282M | 1.3% | 2026-Q2 |
| JANE STREET GROUP, LLC trimmed | 1,410,930 | $278M | 1.2% | 2026-Q2 |
| NORTHERN TRUST CORP added | 1,288,597 | $254M | 1.1% | 2026-Q2 |
| Point72 Asset Management, L.P. trimmed | 1,240,348 | $244M | 1.1% | 2026-Q2 |
| DIMENSIONAL FUND ADVISORS LP trimmed | 1,160,274 | $229M | 1.0% | 2026-Q2 |
| VIKING GLOBAL INVESTORS LP trimmed | 1,153,880 | $227M | 1.0% | 2026-Q2 |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. added | 1,120,952 | $221M | 1.0% | 2026-Q2 |
| BOWEN HANES & CO INC | 1,043,105 | $152M | 0.7% | 2026-Q2 |
| PRICE T ROWE ASSOCIATES INC /MD/ added | 1,021,799 | $201M | 0.9% | 2026-Q2 |
| DENDUR CAPITAL LP trimmed | 1,009,000 | $199M | 0.9% | 2026-Q2 |
| BNP PARIBAS FINANCIAL MARKETS added | 922,903 | $182M | 0.8% | 2026-Q2 |
| VANGUARD FIDUCIARY TRUST CO added | 881,293 | $174M | 0.8% | 2026-Q2 |
| MILLENNIUM MANAGEMENT LLC added | 875,260 | $173M | 0.8% | 2026-Q2 |
| Fisher Asset Management, LLC trimmed | 872,372 | $172M | 0.8% | 2026-Q2 |
| AMERIPRISE FINANCIAL INC trimmed | 858,201 | $169M | 0.8% | 2026-Q2 |
| Bank of New York Mellon Corp trimmed | 857,414 | $169M | 0.8% | 2026-Q2 |
| Artemis Investment Management LLP added | 841,493 | $166M | 0.7% | 2026-Q2 |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP trimmed | 839,786 | $166M | 0.7% | 2026-Q2 |
| POLEN CAPITAL MANAGEMENT LLC new | 819,236 | $161M | 0.7% | 2026-Q2 |
| D. E. Shaw & Co., Inc. trimmed | 815,585 | $161M | 0.7% | 2026-Q2 |
| AMERICAN CENTURY COMPANIES INC trimmed | 765,808 | $151M | 0.7% | 2026-Q2 |
| GOLDMAN SACHS GROUP INC added | 751,276 | $148M | 0.7% | 2026-Q2 |
| Nuveen, LLC added | 737,096 | $145M | 0.6% | 2026-Q2 |
| MARSHALL WACE, LLP added | 709,552 | $140M | 0.6% | 2026-Q2 |
| RAYMOND JAMES FINANCIAL INC added | 667,720 | $132M | 0.6% | 2026-Q2 |
| BARROW HANLEY MEWHINNEY & STRAUSS LLC trimmed | 658,413 | $130M | 0.6% | 2026-Q2 |
| Assenagon Asset Management S.A. added | 657,117 | $130M | 0.6% | 2026-Q2 |
| TWO SIGMA INVESTMENTS, LP added | 636,671 | $125M | 0.6% | 2026-Q2 |
| Freestone Grove Partners LP added | 587,093 | $116M | 0.5% | 2026-Q2 |
| LOOMIS SAYLES & CO L P trimmed | 581,326 | $115M | 0.5% | 2026-Q2 |
| ALLIANCEBERNSTEIN L.P. trimmed | 522,371 | $76M | 0.3% | 2026-Q2 |
| BALYASNY ASSET MANAGEMENT L.P. trimmed | 514,088 | $101M | 0.5% | 2026-Q2 |
| Allspring Global Investments Holdings, LLC trimmed | 502,038 | $96M | 0.4% | 2026-Q2 |
| Holocene Advisors, LP trimmed | 497,600 | $98M | 0.4% | 2026-Q2 |
| CITADEL ADVISORS LLC added | 497,418 | $98M | 0.4% | 2026-Q2 |
| WELLS FARGO & COMPANY/MN added | 483,681 | $95M | 0.4% | 2026-Q2 |
| FEDERATED HERMES, INC. trimmed | 474,180 | $93M | 0.4% | 2026-Q2 |
| JPMORGAN CHASE & CO added | 465,592 | $93M | 0.4% | 2026-Q2 |
| UBS Group AG trimmed | 464,718 | $92M | 0.4% | 2026-Q2 |
| 1832 Asset Management L.P. added | 459,483 | $91M | 0.4% | 2026-Q2 |
| NEUBERGER BERMAN GROUP LLC trimmed | 450,261 | $89M | 0.4% | 2026-Q2 |
| Square Wave Capital, LLC added | 444,800 | $88M | 0.4% | 2026-Q2 |
| DSM CAPITAL PARTNERS LLC new | 441,048 | $87M | 0.4% | 2026-Q2 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC added | 428,271 | $84M | 0.4% | 2026-Q2 |
| FRONTIER CAPITAL MANAGEMENT CO LLC trimmed | 419,968 | $83M | 0.4% | 2026-Q2 |
| BANK OF NOVA SCOTIA trimmed | 417,290 | $82M | 0.4% | 2026-Q2 |
| ENVESTNET ASSET MANAGEMENT INC added | 391,409 | $77M | 0.3% | 2026-Q2 |
| RHUMBLINE ADVISERS added | 376,589 | $74M | 0.3% | 2026-Q2 |
| GAMCO INVESTORS, INC. ET AL trimmed | 358,000 | $71M | 0.3% | 2026-Q2 |
| ING GROEP NV trimmed | 330,300 | $65M | 0.3% | 2026-Q2 |
| CANADA PENSION PLAN INVESTMENT BOARD added | 321,526 | $63M | 0.3% | 2026-Q2 |
| PRINCIPAL FINANCIAL GROUP INC added | 308,372 | $61M | 0.3% | 2026-Q2 |
| Retirement Systems of Alabama trimmed | 286,874 | $57M | 0.3% | 2026-Q2 |
| Clearbridge Investments, LLC new | 280,386 | $55M | 0.2% | 2026-Q2 |
| Swiss National Bank added | 276,400 | $54M | 0.2% | 2026-Q2 |
| Gotham Asset Management, LLC added | 269,572 | $53M | 0.2% | 2026-Q2 |
| VAUGHAN NELSON INVESTMENT MANAGEMENT, L.P. trimmed | 269,170 | $53M | 0.2% | 2026-Q2 |
| Allianz Asset Management GmbH added | 268,032 | $39M | 0.2% | 2026-Q2 |
| California Public Employees Retirement System added | 258,900 | $51M | 0.2% | 2026-Q2 |
| SEGALL BRYANT & HAMILL, LLC trimmed | 242,639 | $48M | 0.2% | 2026-Q2 |
| ROYAL BANK OF CANADA added | 240,438 | $47M | 0.2% | 2026-Q2 |
| BLAIR WILLIAM & CO/IL trimmed | 231,946 | $46M | 0.2% | 2026-Q2 |
| Capital International, Inc./CA/ trimmed | 210,648 | $42M | 0.2% | 2026-Q2 |
| SCHRODER INVESTMENT MANAGEMENT GROUP trimmed | 207,874 | $41M | 0.2% | 2026-Q2 |
| KLCM Advisors, Inc. trimmed | 207,475 | $41M | 0.2% | 2026-Q2 |
| LPL Financial LLC added | 205,781 | $41M | 0.2% | 2026-Q2 |
| Driehaus Capital Management LLC trimmed | 205,124 | $40M | 0.2% | 2026-Q2 |
| HAWK RIDGE CAPITAL MANAGEMENT LP added | 204,700 | $40M | 0.2% | 2026-Q2 |
| JUPITER ASSET MANAGEMENT LTD trimmed | 202,574 | $40M | 0.2% | 2026-Q2 |
| Legal & General Group Plc trimmed | 199,420 | $39M | 0.2% | 2026-Q2 |
| CITIGROUP INC added | 192,174 | $38M | 0.2% | 2026-Q2 |
| PANAGORA ASSET MANAGEMENT INC added | 188,522 | $37M | 0.2% | 2026-Q2 |
| PRUDENTIAL FINANCIAL INC trimmed | 181,276 | $36M | 0.2% | 2026-Q2 |
| Rokos Capital Management LLP added | 180,935 | $36M | 0.2% | 2026-Q2 |
| Yaupon Capital Management LP added | 180,204 | $36M | 0.2% | 2026-Q2 |
| HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND added | 178,880 | $35M | 0.2% | 2026-Q2 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP added | 178,268 | $35M | 0.2% | 2026-Q2 |
| Schonfeld Strategic Advisors LLC added | 177,751 | $35M | 0.2% | 2026-Q2 |
| STATE OF WISCONSIN INVESTMENT BOARD trimmed | 174,589 | $34M | 0.2% | 2026-Q2 |
| DEUTSCHE BANK AG\ added | 162,592 | $32M | 0.1% | 2026-Q2 |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM added | 158,400 | $31M | 0.1% | 2026-Q2 |
| Voleon Capital Management LP added | 154,311 | $30M | 0.1% | 2026-Q2 |
| TUDOR INVESTMENT CORP ET AL added | 148,638 | $29M | 0.1% | 2026-Q2 |
| FIRST TRUST ADVISORS LP added | 148,215 | $29M | 0.1% | 2026-Q2 |
| BARCLAYS PLC added | 139,775 | $28M | 0.1% | 2026-Q2 |
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.