Q2 2026 13F · SEC CIK 1218735
Mason Capital Management LLC
Hedge fundFiled 2026-08-14 for Q2 2026. Open the filing ↗ · All SEC filings ↗
- Reported 13F value
- $607.0M
- Reported positions
- 9
- Top holdings a year, 3 yrs
- -20.1%
- Assets under management
- $2.2B
Mason Capital Management LLC is a hedge fund that reported 9 positions worth $607.0M in its Q2 2026 13F, filed 2026-08-14. Its largest holdings were Ats Corporation (ATS, 77.8%), Brookdale Sr Living Inc (BKD, 6.8%), Enviri Corp (HSC, 6.4%). A portfolio copying its top holdings returned -20.1% a year over the last 3 years, against 20.1% for the S&P 500.
Mason Capital Management LLC holdings all 9 positions.
Weights are shares of the filer's total reported 13F value, compared with Q1 2026. Share changes may reflect splits; weight changes also reflect price moves. A 13F shows long US-listed positions only, up to 135 days after the fact.
| Stock | % of 13F value | Share change | Reported value |
|---|---|---|---|
| ATSAts Corporation | 77.8% | +0.0% | $472.1M |
| BKDBrookdale Sr Living Inc | 6.8% | +15.3% | $41.4M |
| HSCEnviri Corp | 6.4% | -60.6% | $38.9M |
| CCOClear Channel Outdoor Hldgs | 3.9% | +0.0% | $23.8M |
| GRPNGroupon Inc | 2.6% | — | $15.8M |
| RCReady Capital Corp | 1.2% | +0.0% | $7.6M |
| JELDJeld-Wen Hldg Inc | 0.8% | +300.3% | $4.7M |
| LOGCContextlogic Holdings Inc | 0.4% | — | $2.6M |
| 82669G104Signature Bank | 0.0% | +0.0% | $180K |
What Mason Capital Management LLC bought and sold in Q2 2026, against Q1 2026.
New positions
- GRPN Groupon Inc2.6% of 13F
- LOGC Contextlogic Holdings Inc0.4% of 13F
Added to
- JELD Jeld-Wen Hldg Inc+300.3% shares
- BKD Brookdale Sr Living Inc+15.3% shares
Reduced
- HSC Enviri Corp-60.6% shares
Sold out
Nothing sold out.
Share counts compared with the Q1 2026 13F; a split also changes share counts.
How the holdings did against the S&P 500.
- 1 year
- -26.1% /yr
- S&P 500 +20.1%
- 3 years
- -20.1% /yr
- S&P 500 +20.1%
- 5 years
- -14.6% /yr
- S&P 500 +9.6%
A portfolio of the filer's 20 largest 13F positions, weighted by value, bought the trading day after each 13F was filed and held until the next one was: what copying this filer could have earned. 13Fs show long US-listed positions only, so this is an estimate of the stock picks, not the fund's reported returns.
Reported 13F value by quarter.
| Quarter | 13F value | Positions |
|---|---|---|
| Q2 2026 | $607.0M | 9 |
| Q1 2026 | $612.9M | 7 |
| Q4 2025 | $561.6M | 9 |
| Q3 2025 | $491.4M | 6 |
| Q1 2025 | $427.2M | 5 |
| Q3 2024 | $502.6M | 6 |
| Q2 2024 | $538.2M | 6 |
| Q1 2024 | $727.8M | 6 |
| Q4 2023 | $893.9M | 7 |
| Q3 2023 | $1.2B | 8 |
| Q2 2023 | $1.0B | 10 |
| Q1 2023 | $234.2M | 12 |
Questions about Mason Capital Management LLC's portfolio
What stocks does Mason Capital Management LLC own?
Mason Capital Management LLC's latest 13F, for Q2 2026 and filed Aug 14, 2026, lists 9 positions worth $607.0M. The largest are Ats Corporation (ATS) at 77.8%, Brookdale Sr Living Inc (BKD) at 6.8%, Enviri Corp (HSC) at 6.4%, Clear Channel Outdoor Hldgs (CCO) at 3.9% and Groupon Inc (GRPN) at 2.6%.
What did Mason Capital Management LLC buy last quarter?
In Q2 2026, Mason Capital Management LLC added a new position in Groupon Inc (GRPN), a new position in Contextlogic Holdings Inc (LOGC), Jeld-Wen Hldg Inc (JELD) (+300.3% shares) and Brookdale Sr Living Inc (BKD) (+15.3% shares), compared with its Q1 2026 filing.
What did Mason Capital Management LLC sell last quarter?
In Q2 2026, Mason Capital Management LLC Enviri Corp (HSC) (-60.6% shares), compared with its Q1 2026 filing.
How has Mason Capital Management LLC's portfolio performed?
A portfolio copying Mason Capital Management LLC's 20 largest 13F holdings each quarter, from the day each filing was public, returned -20.1% a year over the last 3 years, against +20.1% for the S&P 500. Over 1 year: -26.1% against +20.1%. Over 5 years: -14.6% a year against +9.6%.
When is Mason Capital Management LLC's next 13F filing due?
13F filings are due 45 days after each quarter ends. Mason Capital Management LLC's filing for the quarter ending Sep 30, 2026 is due by Nov 14, 2026; this page updates the day after it is published.
How much money does Mason Capital Management LLC manage?
Mason Capital Management LLC reported $2.2B of regulatory assets under management on its latest SEC Form ADV. Its 13F, which covers only US-listed stocks and options, totals $607.0M.