Who owns ATS Corp /ATS?
Prices and market caps: Cboe delayed data, at least 15 minutes delayed. Not real-time. Fundamentals from company filings.
Institutional ownership of ATS from SEC Form 13F filings across 141 reporting managers. All positions are from one synchronized reporting period — 2026-06-30 books, filed up to 45 days after quarter end — so every row is comparable.
As of the 2026-06-30 reporting period, 141 institutions disclosed 81.6M shares of ATS Corp /ATS worth $2.37B — about 83.2% of shares outstanding; the largest disclosed holder is MASON CAPITAL MANAGEMENT LLC. Source: SEC Form 13F filings, parsed by EvidInvest.
141
13F holders
$2.37B
value, 2026 filers
83.2%
of shares outstanding (81.6M sh)
27
new positions (2026 filers)
Top institutional holders
ordered by shares owned · positions as of 2026-06-30 · % of fund = share of the manager's own book · % of co. = share of ATS's shares outstanding
| # | Manager | Shares | Value | % of fund | % of co. | Δ shares QoQ |
|---|---|---|---|---|---|---|
| 1 | MASON CAPITAL MANAGEMENT LLC | 16.4M | $472.1M | 77.8% | 16.7% | 0.0% |
| 2 | ROYAL BANK OF CANADA | 7.9M | $226.8M | 0.0% | 8% | +1.5% |
| 3 | EdgePoint Investment Group Inc. | 7.0M | $201.7M | 1.5% | 7.1% | -2.3% |
| 4 | Beutel, Goodman & Co Ltd. | 4.8M | $138.2M | 1.0% | 4.9% | -12.1% |
| 5 | TURTLE CREEK ASSET MANAGEMENT INC. | 3.1M | $88.8M | 3.5% | 3.1% | -37.0% |
| 6 | BANK OF MONTREAL /CAN/ | 3.1M | $88.2M | 0.0% | 3.1% | -1.7% |
| 7 | FMR LLC | 2.9M | $83.7M | 0.0% | 3% | +27.6% |
| 8 | FAIRFAX FINANCIAL HOLDINGS LTD/ CAN | 2.5M | $70.5M | 2.7% | 2.5% | 0.0% |
| 9 | VANGUARD CAPITAL MANAGEMENT LLC | 2.4M | $69.1M | 0.0% | 2.4% | +1.3% |
| 10 | Jupiter Topco LLCNEW | 2.3M | $66.9M | 0.0% | 2.4% | new |
| 11 | TD Waterhouse Canada Inc. | 1.7M | $47.4M | 0.1% | 1.7% | +3.0% |
| 12 | Hill City Capital, LP | 1.6M | $47.5M | 1.1% | 1.7% | 0.0% |
| 13 | ACK Asset Management LLC | 1.5M | $43.2M | 5.0% | 1.5% | -18.8% |
| 14 | FIL Ltd | 1.3M | $38.2M | 0.0% | 1.4% | -25.4% |
| 15 | Alberta Investment Management Corp | 1.2M | $33.9M | 0.2% | 1.2% | +25.2% |
| 16 | Scheer, Rowlett & Associates Investment Management Ltd. | 1.2M | $33.8M | 2.4% | 1.2% | -0.6% |
| 17 | BANK OF AMERICA CORP /DE/ | 1.1M | $32.3M | 0.0% | 1.1% | +18.6% |
| 18 | Connor, Clark & Lunn Investment Management Ltd. | 1.1M | $31.4M | 0.1% | 1.1% | -51.9% |
| 19 | NORGES BANKNEW | 1.1M | $31.2M | 0.0% | 1.1% | new |
| 20 | Clearbridge Investments, LLC | 1.1M | $30.5M | 0.0% | 1.1% | -2.8% |
| 21 | Legal & General Group Plc | 1.1M | $30.4M | 0.0% | 1.1% | +72.7% |
| 22 | TD Asset Management Inc | 1.0M | $28.9M | 0.0% | 1% | -29.4% |
| 23 | Marathon Asset Management Ltd | 954,485 | $27.5M | 1.1% | 1% | -12.7% |
| 24 | NATIONAL BANK OF CANADA /FI/ | 855,316 | $24.2M | 0.0% | 0.9% | +31.9% |
| 25 | VAN LANSCHOT KEMPEN INVESTMENT MANAGEMENT N.V. | 795,619 | $32.5M | 0.2% | 0.8% | -7.9% |
Source: SEC Form 13F-HR filings (institutional managers over $100M in US-listed positions). 13Fs disclose long positions only, up to 45 days after quarter end; each manager's latest filed quarter is shown per row and dollar values are the manager's filed marks. Aggregates labeled "2026 filers" count only managers whose latest book is a 2026 quarter. Related: valuation · options positioning · supply chain. Research, not investment advice.