Mason Capital Management LLC reported 8 positions worth $606.84M for the quarter ended Jun 30, 2026, down 0.9% on the prior quarter. It opened 2 new positions, added to 2, trimmed 1 and exited 0. Its largest holding is ATS Corp at 77.8% of the portfolio.
Reported 13F market value at each quarter end. A change mixes trading with price moves in the positions held.
Dollar value of shares bought and sold each quarter, at that quarter’s price. It counts trading only, not price changes.
How many positions were opened, added to, trimmed or closed each quarter.
Share of reported value in each sector at every quarter end.
| Holding | Change | Change % | Trade Value | Weight |
|---|---|---|---|---|
| NVRI Enviri Corp | -2.72M | -60.6% | $59.78M | 6.41% |
No positions were closed this quarter.
| # | Activity | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| 1 | ATS ATS Corp | Industrials | 16.40M | $472.11M | 77.8% | 0 | 0.0% | Unchanged | 16.76% |
| 2 | BKD Brookdale Senior Living Inc. | Healthcare | 2.58M | $41.45M | 6.83% | +342.1K | +15.3% | Added | 1.08% |
| 3 | NVRI Enviri Corp | Industrials | 1.77M | $38.87M | 6.41% | -2.72M | -60.6% | Reduced | 6.28% |
| 4 | CCO Clear Channel Outdoor Holdings, Inc. | Real Estate | 9.83M | $23.78M | 3.92% | 0 | 0.0% | Unchanged | 1.93% |
| 5 | GRPN Groupon, Inc. | Technology | 657.1K | $15.81M | 2.61% | +657.1K | – | New | 1.69% |
| 6 | RC Ready Capital Corp | Financial Services | 4.32M | $7.56M | 1.25% | 0 | 0.0% | Unchanged | 2.61% |
| 7 | JELD JELD-WEN Holding, Inc. | Industrials | 3.11M | $4.66M | 0.769% | +2.33M | +300.3% | Added | 3.6% |
| 8 | LOGC ContextLogic Holdings Inc. | Basic Materials | 291.3K | $2.59M | 0.427% | +291.3K | – | New | 0.64% |
Tip. Select a row to see that position’s full history at Mason Capital Management.
As of its Q2 2026 13F filing, Mason Capital Management LLC’s five largest positions were ATS Corp (ATS) at 77.8%, Brookdale Senior Living Inc. (BKD) at 6.8%, Enviri Corp (NVRI) at 6.4%, Clear Channel Outdoor Holdings, Inc. (CCO) at 3.9%, Groupon, Inc. (GRPN) at 2.6% of the reported portfolio.
Mason Capital Management LLC reported a 13F portfolio worth $606.84M across 8 positions for Q2 2026. That is down 0.9% from the previous quarter.
Its largest purchases by value were Groupon, Inc. ($15.81M), Brookdale Senior Living Inc. ($5.50M), JELD-WEN Holding, Inc. ($3.50M). It opened 2 new positions.
Its largest sales by value were Enviri Corp ($59.78M). It exited 0 positions entirely.
From the Form 13F-HR reports Mason Capital Management LLC files with the SEC each quarter, within 45 days of quarter end. A 13F lists long positions in US-listed equities and options; it excludes short positions, cash, bonds and most non-US holdings.
13F data reflects long positions in US-listed equities and options as reported to the SEC up to 45 days after quarter end. It excludes short positions, cash, bonds and most non-US securities, so it is not a complete picture of a manager’s assets.