Who owns ATS
Which tracked institutional funds hold ATS, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See ATS company fundamentals →
Ownership as of the 2026-Q2 13F filings (latest filed 2026-08-17). 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 ATS while 29 trimmed or exited it between 2026-Q1 and 2026-Q2 — 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
ATS’s largest tracked holder by dollar value, MASON CAPITAL MANAGEMENT LLC, sizes it at 77.8% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 77.8pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in ATS 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 133 tracked filers holding ATS, 78 increased or opened the position and 62 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 ATS 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 14
- Jupiter Topco LLC$67M
- Langdon Equity Partners$17M
- Roubaix Capital, LLC$7M
- NewGen Asset Management Ltd$4M
- Polar Asset Management Partners Inc.$3M
- K.J. Harrison & Partners Inc$3M
Full exits 9
- Beutel, Goodman & Co Ltd.$153M
- JANUS HENDERSON GROUP PLC$65M
- Vinva Investment Management Ltd$37M
- PRINCIPAL FINANCIAL GROUP INC$17M
- Van Berkom & Associates Inc.$7M
- ROYCE & ASSOCIATES LP$5M
Largest adds
- FMR LLC$20M
- Legal & General Group Plc$13M
- MASON CAPITAL MANAGEMENT LLC$10M
- TORONTO DOMINION BANK$9M
- ROYAL BANK OF CANADA$8M
- Alberta Investment Management Corp$7M
Largest trims
- TURTLE CREEK ASSET MANAGEMENT INC.$204M
- Connor, Clark & Lunn Investment Management Ltd.$32M
- FIL Ltd$12M
- TD Asset Management Inc$11M
- ACK Asset Management LLC$9M
- Invesco Ltd.$8M
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 |
|---|---|---|---|---|
| MASON CAPITAL MANAGEMENT LLC | 16,404,170 | $472M | 21.3% | 2026-Q2 |
| ROYAL BANK OF CANADA added | 7,881,423 | $227M | 10.2% | 2026-Q2 |
| EdgePoint Investment Group Inc. trimmed | 7,004,577 | $202M | 9.1% | 2026-Q2 |
| TURTLE CREEK ASSET MANAGEMENT INC. trimmed | 3,084,567 | $89M | 4.0% | 2026-Q2 |
| BANK OF MONTREAL /CAN/ trimmed | 3,062,973 | $88M | 4.0% | 2026-Q2 |
| FMR LLC added | 2,905,456 | $84M | 3.8% | 2026-Q2 |
| FAIRFAX FINANCIAL HOLDINGS LTD/ CAN | 2,486,400 | $70M | 3.2% | 2026-Q2 |
| VANGUARD CAPITAL MANAGEMENT LLC added | 2,398,431 | $69M | 3.1% | 2026-Q2 |
| Jupiter Topco LLC new | 2,322,073 | $67M | 3.0% | 2026-Q2 |
| TD Waterhouse Canada Inc. added | 1,683,683 | $47M | 2.1% | 2026-Q2 |
| Hill City Capital, LP | 1,649,857 | $47M | 2.1% | 2026-Q2 |
| ACK Asset Management LLC trimmed | 1,500,000 | $43M | 1.9% | 2026-Q2 |
| FIL Ltd trimmed | 1,326,851 | $38M | 1.7% | 2026-Q2 |
| Alberta Investment Management Corp added | 1,177,491 | $34M | 1.5% | 2026-Q2 |
| Scheer, Rowlett & Associates Investment Management Ltd. trimmed | 1,175,268 | $34M | 1.5% | 2026-Q2 |
| BANK OF AMERICA CORP /DE/ added | 1,122,152 | $32M | 1.5% | 2026-Q2 |
| Connor, Clark & Lunn Investment Management Ltd. trimmed | 1,089,460 | $31M | 1.4% | 2026-Q2 |
| NORGES BANK added | 1,084,181 | $31M | 1.4% | 2026-Q2 |
| Clearbridge Investments, LLC trimmed | 1,060,487 | $31M | 1.4% | 2026-Q2 |
| Legal & General Group Plc added | 1,056,408 | $30M | 1.4% | 2026-Q2 |
| TD Asset Management Inc trimmed | 1,003,596 | $29M | 1.3% | 2026-Q2 |
| Marathon Asset Management Ltd trimmed | 954,485 | $28M | 1.2% | 2026-Q2 |
| NATIONAL BANK OF CANADA /FI/ added | 855,316 | $24M | 1.1% | 2026-Q2 |
| VAN LANSCHOT KEMPEN INVESTMENT MANAGEMENT N.V. trimmed | 795,619 | $33M | 1.5% | 2026-Q2 |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. added | 788,784 | $23M | 1.0% | 2026-Q2 |
| VANGUARD FIDUCIARY TRUST CO trimmed | 724,271 | $21M | 0.9% | 2026-Q2 |
| Langdon Equity Partners new | 600,000 | $17M | 0.8% | 2026-Q2 |
| MASSACHUSETTS FINANCIAL SERVICES CO /MA/ added | 540,733 | $22M | 1.0% | 2026-Q2 |
| MACKENZIE FINANCIAL CORP trimmed | 524,774 | $21M | 1.0% | 2026-Q2 |
| TORONTO DOMINION BANK added | 406,916 | $12M | 0.5% | 2026-Q2 |
| Public Sector Pension Investment Board added | 378,001 | $11M | 0.5% | 2026-Q2 |
| 1832 Asset Management L.P. trimmed | 355,745 | $10M | 0.5% | 2026-Q2 |
| Waratah Capital Advisors Ltd. added | 334,923 | $10M | 0.4% | 2026-Q2 |
| CIBC WORLD MARKET INC. trimmed | 327,087 | $9M | 0.4% | 2026-Q2 |
| ArrowMark Colorado Holdings LLC added | 280,000 | $8M | 0.4% | 2026-Q2 |
| Vanguard Global Advisers, LLC added | 274,103 | $8M | 0.4% | 2026-Q2 |
| Roubaix Capital, LLC added | 246,909 | $7M | 0.3% | 2026-Q2 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC added | 243,525 | $7M | 0.3% | 2026-Q2 |
| MORGAN STANLEY added | 234,236 | $7M | 0.3% | 2026-Q2 |
| GOLDMAN SACHS GROUP INC added | 223,762 | $6M | 0.3% | 2026-Q2 |
| UBS Group AG trimmed | 222,553 | $6M | 0.3% | 2026-Q2 |
| SCOTIA CAPITAL INC. added | 212,719 | $6M | 0.3% | 2026-Q2 |
| Dixon Mitchell Investment Counsel Inc. | 211,025 | $6M | 0.3% | 2026-Q2 |
| JANE STREET GROUP, LLC added | 199,635 | $6M | 0.3% | 2026-Q2 |
| Granite Investment Partners, LLC added | 195,894 | $6M | 0.3% | 2026-Q2 |
| Focus Partners Wealth | 181,975 | $5M | 0.2% | 2026-Q2 |
| FIRST TRUST ADVISORS LP added | 181,592 | $5M | 0.2% | 2026-Q2 |
| Swiss National Bank added | 168,000 | $5M | 0.2% | 2026-Q2 |
| DIMENSIONAL FUND ADVISORS LP added | 167,149 | $5M | 0.2% | 2026-Q2 |
| Candelo Capital Management LP added | 165,100 | $5M | 0.2% | 2026-Q2 |
| Delaney Capital Management Ltd. added | 160,392 | $5M | 0.2% | 2026-Q2 |
| NewGen Asset Management Ltd trimmed | 150,000 | $4M | 0.2% | 2026-Q2 |
| CIBC Asset Management Inc added | 138,246 | $4M | 0.2% | 2026-Q2 |
| Front Street Capital Management, Inc. trimmed | 124,973 | $4M | 0.2% | 2026-Q2 |
| LOUISBOURG INVESTMENTS INC. added | 111,104 | $3M | 0.1% | 2026-Q2 |
| Polar Asset Management Partners Inc. trimmed | 105,203 | $3M | 0.1% | 2026-Q2 |
| BRITISH COLUMBIA INVESTMENT MANAGEMENT Corp added | 101,546 | $3M | 0.1% | 2026-Q2 |
| K.J. Harrison & Partners Inc new | 100,000 | $3M | 0.1% | 2026-Q2 |
| MONTRUSCO BOLTON INVESTMENTS INC. trimmed | 99,056 | $3M | 0.1% | 2026-Q2 |
| SEI INVESTMENTS CO trimmed | 97,376 | $3M | 0.1% | 2026-Q2 |
| PCJ Investment Counsel Ltd. added | 85,640 | $2M | 0.1% | 2026-Q2 |
| LAZARD ASSET MANAGEMENT LLC added | 83,052 | $2M | 0.1% | 2026-Q2 |
| Canoe Financial LP trimmed | 83,024 | $2M | 0.1% | 2026-Q2 |
| HALLSTATT ADVISORS L.P. new | 83,020 | $2M | 0.1% | 2026-Q2 |
| CITADEL ADVISORS LLC added | 82,308 | $2M | 0.1% | 2026-Q2 |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE trimmed | 73,654 | $2M | 0.1% | 2026-Q2 |
| GEODE CAPITAL MANAGEMENT, LLC added | 69,598 | $2M | 0.1% | 2026-Q2 |
| VANGUARD ASSET MANAGEMENT, Ltd | 66,830 | $2M | 0.1% | 2026-Q2 |
| CenterBook Partners LP new | 65,180 | $2M | 0.1% | 2026-Q2 |
| Nuveen, LLC | 62,584 | $2M | 0.1% | 2026-Q2 |
| Caldwell Investment Management Ltd. | 60,800 | $2M | 0.1% | 2026-Q2 |
| BOOTHBAY FUND MANAGEMENT, LLC added | 59,867 | $2M | 0.1% | 2026-Q2 |
| Federation des caisses Desjardins du Quebec trimmed | 54,947 | $2M | 0.1% | 2026-Q2 |
| Zurcher Kantonalbank (Zurich Cantonalbank) added | 54,361 | $2M | 0.1% | 2026-Q2 |
| VAN ECK ASSOCIATES CORP added | 46,507 | $1M | 0.1% | 2026-Q2 |
| GUARDIAN CAPITAL LP trimmed | 46,433 | $1M | 0.1% | 2026-Q2 |
| INTACT INVESTMENT MANAGEMENT INC. trimmed | 40,489 | $1M | 0.1% | 2026-Q2 |
| Aviso Financial Inc. trimmed | 40,111 | $1M | 0.1% | 2026-Q2 |
| PenderFund Capital Management Ltd. added | 37,700 | $1M | 0.0% | 2026-Q2 |
| CITIGROUP INC added | 36,651 | $1M | 0.0% | 2026-Q2 |
| BANK OF NOVA SCOTIA TRUST CO added | 35,291 | $1M | 0.0% | 2026-Q2 |
| XTX Topco Ltd added | 35,013 | $1M | 0.0% | 2026-Q2 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP added | 34,791 | $1M | 0.0% | 2026-Q2 |
| AMERICAN CENTURY COMPANIES INC new | 32,500 | $937K | 0.0% | 2026-Q2 |
| Police & Firemen's Retirement System of New Jersey added | 31,937 | $920K | 0.0% | 2026-Q2 |
| Engineers Gate Manager LP added | 31,363 | $903K | 0.0% | 2026-Q2 |
| Verition Fund Management LLC added | 29,513 | $849K | 0.0% | 2026-Q2 |
| PUBLIC EMPLOYEES RETIREMENT SYSTEM OF OHIO added | 28,366 | $817K | 0.0% | 2026-Q2 |
| FRANKLIN RESOURCES INC trimmed | 25,412 | $732K | 0.0% | 2026-Q2 |
| Squarepoint Ops LLC new | 24,760 | $713K | 0.0% | 2026-Q2 |
| SIG North Trading, ULC trimmed | 22,575 | $650K | 0.0% | 2026-Q2 |
| ExodusPoint Capital Management, LP added | 22,100 | $636K | 0.0% | 2026-Q2 |
| Vanguard Investments Australia, Ltd. added | 21,874 | $630K | 0.0% | 2026-Q2 |
| WELLS FARGO & COMPANY/MN added | 19,748 | $568K | 0.0% | 2026-Q2 |
| BARCLAYS PLC added | 16,814 | $484K | 0.0% | 2026-Q2 |
| ALLIANCEBERNSTEIN L.P. added | 16,380 | $462K | 0.0% | 2026-Q2 |
| Pictet Asset Management Holding SA trimmed | 15,987 | $461K | 0.0% | 2026-Q2 |
| Purpose Unlimited Inc. trimmed | 15,754 | $454K | 0.0% | 2026-Q2 |
| Northwest & Ethical Investments L.P. added | 15,573 | $448K | 0.0% | 2026-Q2 |
| Aberdeen Group plc trimmed | 13,483 | $388K | 0.0% | 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.