Mason Capital Management LLC
In its 13F for Q2 2026 (holdings as of June 30, 2026, filed August 14, 2026), Mason Capital Management LLC reported 9 stock positions worth $607.0 million. Its top holding was Ats (ATS) at 77.8% of the portfolio, followed by Brookdale Senior Living (BKD, 6.8%) and Enviri (NVRI, 6.4%). Compared with Q1 2026, it opened 2 new positions, added to 2 and reduced 1. The biggest buy was a new position in Groupon (GRPN) and the biggest sale Enviri (NVRI, shares −61%).
- Most Recent 13F
- Q2 2026
- Location
- NEW YORK, NY
- CIK
- 0001218735
- Portfolio Value
- $607.0M (Q2 2026)
- SEC Filing
- 0001104659-26-097052 ↗ filed Aug 14, 2026
Holdings Value
Holdings 9 stocks · $607.0M
| ATS Ats Corp. | 77.78% | 16,404,170 | $472.1M | No change |
| BKD Brookdale Senior Living Inc. | 6.83% | 2,575,826 | $41.4M | Add +15.3% |
| NVRI Enviri Corp. | 6.40% | 1,770,959 | $38.9M | Reduce -60.6% |
| CCO Clear Channel Outdoor Holdin | 3.92% | 9,828,401 | $23.8M | No change |
| GRPN Groupon Inc. | 2.60% | 657,144 | $15.8M | New |
| RC Ready Capital Corp. | 1.25% | 4,319,933 | $7.6M | No change |
| JELD Jeld-Wen Holding Inc. | 0.77% | 3,109,621 | $4.7M | Add +300.3% |
| LOGC Contextlogic Holdings Inc. | 0.43% | 291,341 | $2.6M | New |
| SBNY Signature Bank | 0.03% | 400,000 | $180K | No change |
Portfolio Sells Q1 2026 → Q2 2026
| NVRI Enviri Corp. | Reduce -60.6% | 6.40% | −7.99 |
Portfolio Buys Q1 2026 → Q2 2026
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 |