Who owns ATO (ATO)
Which tracked institutional funds hold ATO, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See ATO 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
The tracked-fund tape on ATO is one-sided between 2025-Q4 and 2026-Q1: 334 added or opened and 112 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
ATO’s largest tracked holder by dollar value, VANGUARD GROUP 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 ATO more heavily than its largest holder by dollar value does.
Book-share is each fund’s reported value in ATO 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 1015 tracked filers holding ATO, 544 increased or opened the position and 419 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 ATO 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 48
- VANGUARD CAPITAL MANAGEMENT LLC$2.0B
- VANGUARD PORTFOLIO MANAGEMENT LLC$1.7B
- Capital Research Global Investors$741M
- VANGUARD FIDUCIARY TRUST CO$172M
- Vanguard Global Advisers, LLC$67M
- VANGUARD ASSET MANAGEMENT, Ltd$56M
Full exits 44
- VANGUARD GROUP INC$3.5B
- Pacer Advisors, Inc.$46M
- MIZUHO MARKETS AMERICAS LLC$40M
- Skandinaviska Enskilda Banken AB (publ)$24M
- SUSQUEHANNA FUNDAMENTAL INVESTMENTS, LLC$13M
- D. E. Shaw & Co., Inc.$12M
Largest adds
- STATE STREET CORP$293M
- GOLDMAN SACHS GROUP INC$149M
- BANK OF AMERICA CORP /DE/$142M
- WELLINGTON MANAGEMENT GROUP LLP$105M
- BNP PARIBAS FINANCIAL MARKETS$101M
- Amundi$95M
Largest trims
- Capital International Investors$640M
- PRICE T ROWE ASSOCIATES INC /MD/$604M
- Aristotle Capital Management, LLC$169M
- BlackRock, Inc.$160M
- NORGES BANK$110M
- NORTHWESTERN MUTUAL WEALTH MANAGEMENT CO$108M
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 | 14,584,944 | $2.7B | 9.1% | 2026-Q1 |
| STATE STREET CORP added | 11,372,750 | $2.1B | 7.1% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 10,735,547 | $2.0B | 6.7% | 2026-Q1 |
| WELLINGTON MANAGEMENT GROUP LLP trimmed | 9,651,472 | $1.8B | 6.0% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 9,285,633 | $1.7B | 5.8% | 2026-Q1 |
| Capital International Investors trimmed | 7,326,778 | $1.4B | 4.6% | 2026-Q1 |
| Aristotle Capital Management, LLC trimmed | 4,866,481 | $899M | 3.1% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 4,336,996 | $798M | 2.7% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 4,199,433 | $776M | 2.6% | 2026-Q1 |
| Capital Research Global Investors new | 4,010,550 | $741M | 2.5% | 2026-Q1 |
| Invesco Ltd. trimmed | 2,977,272 | $550M | 1.9% | 2026-Q1 |
| PRICE T ROWE ASSOCIATES INC /MD/ trimmed | 2,715,107 | $502M | 1.7% | 2026-Q1 |
| DEUTSCHE BANK AG\ trimmed | 2,547,037 | $470M | 1.6% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC added | 1,935,162 | $357M | 1.2% | 2026-Q1 |
| MASSACHUSETTS FINANCIAL SERVICES CO /MA/ trimmed | 1,772,601 | $331M | 1.1% | 2026-Q1 |
| Legal & General Group Plc added | 1,616,380 | $299M | 1.0% | 2026-Q1 |
| NORTHERN TRUST CORP added | 1,549,694 | $286M | 1.0% | 2026-Q1 |
| DZ BANK AG Deutsche Zentral Genossenschafts Bank, Frankfurt am Main added | 1,490,653 | $275M | 0.9% | 2026-Q1 |
| WELLS FARGO & COMPANY/MN trimmed | 1,329,328 | $246M | 0.8% | 2026-Q1 |
| Amundi added | 1,302,886 | $241M | 0.8% | 2026-Q1 |
| Perpetual Ltd trimmed | 1,240,469 | $229M | 0.8% | 2026-Q1 |
| RAYMOND JAMES FINANCIAL INC added | 1,206,752 | $223M | 0.8% | 2026-Q1 |
| NORGES BANK trimmed | 1,432,906 | $221M | 0.8% | 2026-Q1 |
| Pictet Asset Management Holding SA added | 1,175,415 | $217M | 0.7% | 2026-Q1 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC added | 1,063,678 | $196M | 0.7% | 2026-Q1 |
| SFMG, LLC trimmed | 1,058,545 | $196M | 0.7% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC added | 1,036,621 | $191M | 0.6% | 2026-Q1 |
| ProShare Advisors LLC added | 1,023,862 | $189M | 0.6% | 2026-Q1 |
| AMERICAN CENTURY COMPANIES INC trimmed | 1,002,458 | $185M | 0.6% | 2026-Q1 |
| Nuveen, LLC added | 947,508 | $175M | 0.6% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 930,642 | $172M | 0.6% | 2026-Q1 |
| Bank of New York Mellon Corp trimmed | 892,696 | $165M | 0.6% | 2026-Q1 |
| GQG Partners LLC added | 887,204 | $164M | 0.6% | 2026-Q1 |
| PNC FINANCIAL SERVICES GROUP, INC. added | 886,291 | $164M | 0.6% | 2026-Q1 |
| BNP PARIBAS FINANCIAL MARKETS added | 834,718 | $154M | 0.5% | 2026-Q1 |
| AQR CAPITAL MANAGEMENT LLC added | 820,885 | $151M | 0.5% | 2026-Q1 |
| COHEN & STEERS, INC. added | 800,246 | $148M | 0.5% | 2026-Q1 |
| HSBC HOLDINGS PLC trimmed | 780,184 | $144M | 0.5% | 2026-Q1 |
| CBRE INVESTMENT MANAGEMENT LISTED REAL ASSETS LLC added | 757,953 | $140M | 0.5% | 2026-Q1 |
| DIMENSIONAL FUND ADVISORS LP added | 752,986 | $139M | 0.5% | 2026-Q1 |
| CITADEL ADVISORS LLC added | 751,604 | $139M | 0.5% | 2026-Q1 |
| UBS Group AG added | 718,687 | $133M | 0.5% | 2026-Q1 |
| SILVERCREST ASSET MANAGEMENT GROUP LLC trimmed | 707,225 | $131M | 0.4% | 2026-Q1 |
| ENVESTNET ASSET MANAGEMENT INC added | 674,566 | $125M | 0.4% | 2026-Q1 |
| PFA Pension, Forsikringsaktieselskab added | 668,040 | $123M | 0.4% | 2026-Q1 |
| DUFF & PHELPS INVESTMENT MANAGEMENT CO trimmed | 607,945 | $112M | 0.4% | 2026-Q1 |
| NEUBERGER BERMAN GROUP LLC added | 601,090 | $111M | 0.4% | 2026-Q1 |
| Chevy Chase Trust Holdings, LLC added | 518,713 | $96M | 0.3% | 2026-Q1 |
| SEI INVESTMENTS CO trimmed | 512,825 | $95M | 0.3% | 2026-Q1 |
| PRINCIPAL FINANCIAL GROUP INC added | 507,404 | $94M | 0.3% | 2026-Q1 |
| ROYAL BANK OF CANADA trimmed | 503,937 | $93M | 0.3% | 2026-Q1 |
| Nilsine Partners, LLC trimmed | 491,331 | $91M | 0.3% | 2026-Q1 |
| Swiss National Bank added | 474,700 | $88M | 0.3% | 2026-Q1 |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM trimmed | 473,753 | $88M | 0.3% | 2026-Q1 |
| HUNTINGTON NATIONAL BANK added | 467,982 | $86M | 0.3% | 2026-Q1 |
| Clark Capital Management Group, Inc. added | 432,477 | $80M | 0.3% | 2026-Q1 |
| EARNEST PARTNERS LLC trimmed | 422,810 | $78M | 0.3% | 2026-Q1 |
| Mitsubishi UFJ Asset Management Co., Ltd. added | 397,172 | $73M | 0.2% | 2026-Q1 |
| Sumitomo Mitsui Trust Group, Inc. trimmed | 394,689 | $73M | 0.2% | 2026-Q1 |
| AVIVA PLC added | 383,702 | $71M | 0.2% | 2026-Q1 |
| BARCLAYS PLC added | 373,342 | $69M | 0.2% | 2026-Q1 |
| Energy Income Partners, LLC added | 363,311 | $67M | 0.2% | 2026-Q1 |
| Vanguard Global Advisers, LLC new | 360,844 | $67M | 0.2% | 2026-Q1 |
| T. Rowe Price Investment Management, Inc. added | 358,652 | $66M | 0.2% | 2026-Q1 |
| RHUMBLINE ADVISERS trimmed | 353,960 | $65M | 0.2% | 2026-Q1 |
| JENNISON ASSOCIATES LLC trimmed | 346,090 | $64M | 0.2% | 2026-Q1 |
| FIRST TRUST ADVISORS LP trimmed | 340,408 | $63M | 0.2% | 2026-Q1 |
| BENJAMIN EDWARDS INC trimmed | 339,303 | $63M | 0.2% | 2026-Q1 |
| BAHL & GAYNOR INC added | 335,750 | $62M | 0.2% | 2026-Q1 |
| Capital International, Inc./CA/ added | 325,613 | $60M | 0.2% | 2026-Q1 |
| Boston Trust Walden Corp trimmed | 324,927 | $60M | 0.2% | 2026-Q1 |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE trimmed | 323,423 | $60M | 0.2% | 2026-Q1 |
| KBC Group NV trimmed | 316,327 | $58M | 0.2% | 2026-Q1 |
| TORONTO DOMINION BANK trimmed | 309,461 | $57M | 0.2% | 2026-Q1 |
| Vest Financial, LLC added | 307,562 | $57M | 0.2% | 2026-Q1 |
| VANGUARD ASSET MANAGEMENT, Ltd new | 303,715 | $56M | 0.2% | 2026-Q1 |
| COMMONWEALTH OF PENNSYLVANIA PUBLIC SCHOOL EMPLS RETRMT SYS trimmed | 301,973 | $56M | 0.2% | 2026-Q1 |
| NEW YORK STATE COMMON RETIREMENT FUND trimmed | 295,457 | $55M | 0.2% | 2026-Q1 |
| California Public Employees Retirement System trimmed | 290,843 | $54M | 0.2% | 2026-Q1 |
| NOMURA ASSET MANAGEMENT CO LTD added | 289,580 | $53M | 0.2% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC added | 261,421 | $48M | 0.2% | 2026-Q1 |
| SCHRODER INVESTMENT MANAGEMENT GROUP added | 259,231 | $48M | 0.2% | 2026-Q1 |
| ROYAL LONDON ASSET MANAGEMENT LTD added | 255,035 | $47M | 0.2% | 2026-Q1 |
| Munich Reinsurance Co Stock Corp in Munich trimmed | 251,761 | $47M | 0.2% | 2026-Q1 |
| Aventail Capital Group, LP added | 247,838 | $46M | 0.2% | 2026-Q1 |
| National Pension Service added | 244,687 | $45M | 0.2% | 2026-Q1 |
| CITIGROUP INC trimmed | 241,707 | $45M | 0.2% | 2026-Q1 |
| Partners Group Holding AG trimmed | 238,206 | $44M | 0.1% | 2026-Q1 |
| STIFEL FINANCIAL CORP added | 232,998 | $43M | 0.1% | 2026-Q1 |
| Aberdeen Group plc added | 228,217 | $42M | 0.1% | 2026-Q1 |
| Clearbridge Investments, LLC added | 221,869 | $41M | 0.1% | 2026-Q1 |
| M&G PLC trimmed | 201,418 | $37M | 0.1% | 2026-Q1 |
| EXCHANGE TRADED CONCEPTS, LLC added | 195,457 | $36M | 0.1% | 2026-Q1 |
| LPL Financial LLC added | 194,277 | $36M | 0.1% | 2026-Q1 |
| Allspring Global Investments Holdings, LLC added | 189,256 | $35M | 0.1% | 2026-Q1 |
| Eurizon Capital SGR S.p.A. trimmed | 189,350 | $35M | 0.1% | 2026-Q1 |
| CANADA LIFE ASSURANCE Co trimmed | 188,054 | $35M | 0.1% | 2026-Q1 |
| VANGUARD GROUP INC added | 21,032,449 | $3.5B | 12.0% | 2025-Q4 stale |
| MEAG MUNICH ERGO, Kapitalanlagegesellschaft mbH trimmed | 275,000 | $42M | 0.1% | 2025-Q2 stale |
| MIZUHO MARKETS AMERICAS LLC trimmed | 240,814 | $40M | 0.1% | 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.