Mason Capital Management LLC
In its 13F for Q3 2025 (holdings as of September 30, 2025, filed November 14, 2025), Mason Capital Management LLC reported 6 stock positions worth $491.4 million. Its top holding was Ats (ATS) at 83.0% of the portfolio, followed by Kenvue (KVUE, 8.6%) and Brookdale Senior Living (BKD, 4.3%). Compared with Q2 2025, it opened 3 new positions and sold out of 1. The biggest buy was a new position in Kenvue (KVUE) and the biggest sale an exit from Cohen Circle Acquisitio Class A (CCIR).
- Most Recent 13F
- Q2 2026
- Location
- NEW YORK, NY
- CIK
- 0001218735
- Portfolio Value
- $491.4M (Q3 2025)
- SEC Filing
- 0001104659-25-111862 ↗ filed Nov 14, 2025
Holdings Value
Holdings 6 stocks · $491.4M
| ATS Ats Corp. | 82.99% | 15,563,568 | $407.8M | No change |
| KVUE Kenvue Inc. | 8.57% | 2,595,000 | $42.1M | New |
| BKD Brookdale Senior Living Inc. | 4.27% | 2,475,964 | $21.0M | New |
| CCO Clear Channel Outdoor Holdin | 3.16% | 9,828,401 | $15.5M | No change |
| MLAB Mesa Laboratories Inc. | 0.96% | 70,300 | $4.7M | New |
| SBNY Signature Bank | 0.05% | 400,000 | $260K | No change |
Portfolio Sells Q2 2025 → Q3 2025
| CCIR Cohen Circle Acquisitio Class A | Sold out | 0.00% | −0.70 |
Portfolio Buys Q2 2025 → Q3 2025
All Filings
| Quarter | Positions | 13F Reported Value | Top Holdings |
|---|---|---|---|
| Q2 2026 | 9 | $607.0M | ATS, BKD, NVRI, CCO, GRPN |
| Q1 2026 | 7 | $612.9M | ATS, NVRI, BKD, CCO, RC |
| Q4 2025 | 9 | $561.6M | ATS, BKD, SOLS, CCO, JBS |
| Q3 2025 | 6 | $491.4M | ATS, KVUE, BKD, CCO, MLAB |
| Q2 2025 | 4 | $511.5M | ATS, CCO, CCIR, SBNY |
| Q1 2025 | 5 | $427.2M | ATS, PARAA, CCO, CCIR, SBNY |
| Q4 2024 | 4 | $470.5M | ATS, CCO, RC, SBNY |
| Q3 2024 | 6 | $502.6M | ATS, MDRX, BARNES GROUP INC, CCO, RC |
| Q2 2024 | 6 | $538.2M | ATS, BARNES GROUP INC, CCO, MDRX, IIIV |
| Q1 2024 | 6 | $727.8M | ATS, BARNES GROUP INC, SDRL, CCO, MDRX |