Mason Capital Management LLC
Mason Capital Management LLC reported 9 US-listed holdings worth $607.0 million in its 13F for the quarter ended 30 June 2026, filed 14 August 2026. Its largest: Ats Corporation (77.8%), Brookdale SR Living Inc. (6.8%) and Enviri Corp. (6.4%). Against the quarter before, it opened 2 positions, added to 2, trimmed 1 and sold out of 0.
The 9 largest of its 9 positions, each sized by its share of the reported holdings, coloured by the change in shares against Q1 2026.
What the fund reported holding at each quarter's end; hover a bar for the number of positions
What its reported holdings returned
Held through each quarter, the holdings it reported returned +8.2% over the 7 quarters to 30 June 2026, against +30.2% for the S&P 500.
Not the fund's own return: each 13F's holdings are kept unchanged until the next one, so trades inside a quarter, dividends, cash and fees are left out. A rough guide to how its picks have done over time.
What it did on the quarter
Its positions against its 13F for the quarter to 31 March 2026; a change under 0.1% of a position counts as held
Opened 2
- Groupon Inc. GRPN$15.8 million
- ContextLogic Holdings Inc LOGCD$2.6 million
Added to 2
- Brookdale SR Living Inc. BKD+342,085 shares · +15%
- Jeld-Wen Hldg Inc. JELD+2.3 million shares · +300%
Trimmed 1
- Enviri Corp. NVRI-2.7 million shares · -61%
What it holds
| Company | Shares | Value | Of its book | Change in shares |
|---|---|---|---|---|
| Ats Corporation ATS | 16.4M | $472.1 million | 77.78% | no change |
| Brookdale SR Living Inc. BKD | 2.6M | $41.4 million | 6.83% | +342.1K |
| Enviri Corp. NVRI | 1.8M | $38.9 million | 6.40% | -2.7M |
| Clear Channel Outdoor Hldgs CCO | 9.8M | $23.8 million | 3.92% | no change |
| Groupon Inc. GRPN | 657.1K | $15.8 million | 2.60% | new |
| Ready Capital Corp. RC | 4.3M | $7.6 million | 1.25% | no change |
| Jeld-Wen Hldg Inc. JELD | 3.1M | $4.7 million | 0.77% | +2.3M |
| ContextLogic Holdings Inc LOGCD | 291.3K | $2.6 million | 0.43% | new |
| Signature Bank SBNY | 400.0K | $180,000 | 0.03% | no change |