Institutional Manager · CIK 0001218735
MASON CAPITAL MANAGEMENT LLC
New York, NY · File #028-10413
Latest AUM
$561.6M
Positions
9
Top-10 Concentration
100.0%
Filings
12
Sector Allocation
Filing History
View all filings →- 13F HOLDINGS REPORTQ/E Dec 20259 pos · $561.6M
- 13F HOLDINGS REPORTQ/E Sep 20256 pos · $491.4M
- 13F HOLDINGS REPORTQ/E Jun 20254 pos · $511.5M
- 13F HOLDINGS REPORTQ/E Mar 20255 pos · $427.2M
- 13F HOLDINGS REPORTQ/E Dec 20244 pos · $470.5M
- 13F HOLDINGS REPORTQ/E Sep 20246 pos · $502.6M
- 13F HOLDINGS REPORTQ/E Jun 20246 pos · $538.2M
- 13F HOLDINGS REPORTQ/E Mar 20246 pos · $727.8M
- 13F HOLDINGS REPORTQ/E Dec 20238 pos · $1.16B
- 13F HOLDINGS REPORTQ/E Sep 202310 pos · $1.03B
- 13F HOLDINGS REPORTQ/E Jun 202312 pos · $234.2M
- 13F HOLDINGS REPORTQ/E Mar 202313 pos · $609.2M
Top 9 Holdings — Dec 2025
| # | Issuer | Ticker | Shares | Value | % of Portfolio |
|---|---|---|---|---|---|
| 1 | ATS CORPORATION | ATS | 15,563,568 | $428.6M | 76.32% |
| 2 | BROOKDALE SENIOR LIVING INC | 112463104 | 3,585,941 | $38.7M | 6.89% |
| 3 | SOLSTICE ADV MATERIALS INC | 83443Q103 | 633,801 | $30.8M | 5.48% |
| 4 | CLEAR CHANNEL OUTDOOR HLDGS | CCO | 9,828,401 | $21.7M | 3.87% |
| 5 | JBS N.V. | JBS | 1,306,000 | $18.8M | 3.35% |
| 6 | BORR DRILLING LTD | BORR | 2,182,136 | $8.8M | 1.57% |
| 7 | READY CAPITAL CORP | RC-PE | 3,776,139 | $8.2M | 1.47% |
| 8 | MESA LABORATORIES INC | 59064R109 | 70,300 | $5.5M | 0.98% |
| 9 | SIGNATURE BANK | 82669G104 | 400,000 | $404,000 | 0.07% |