MASON CAPITAL MANAGEMENT LLC
CIK 1218735 · View on SEC EDGAR ↗
- Portfolio value
- $607.0M
- Positions
- 9
- As of
- June 30, 2026
Portfolio value QoQ: -1.0% 13F does not disclose cash
- Top 10 holdings weight
- 100.00%
- Top 25 holdings weight
- 100.00%
- Positions above 1%
- 6
- Effective number of positions
- 1.6
Based on 13F long-equity holdings only (cash, bonds, shorts not disclosed)
Turnover Q2 2026: 4.49% Est. buys $27,407,072 · sells $59,782,515
Median holding: 2.0 quarters Tracked Q4 2024–Q2 2026 · 56.2% still held
- New positions
- 2
- Increased
- 2
- Decreased
- 1
- Closed
- 4
On this page
- Performance vs S&P How this manager's 13F portfolio performed against the S&P 500.
- Sector breakdown How the portfolio splits across market sectors.
- Portfolio Every stock this institution reports holding, from its latest 13F.
- Biggest new bets Brand-new positions opened in the latest quarter.
- Top moves The biggest position increases and decreases this quarter.
- Exited positions Positions the manager fully sold out of last quarter.
Performance vs S&P 500
Annualized: +2.7% · S&P 500: +18.0%
Approximates a buy-and-hold portfolio built from quarterly SEC 13F snapshots. Excludes cash, short positions, options/derivatives, and non-13(f) securities — reflects the disclosed long-equity book only, not total fund AUM. SEC filing lag is up to 45 days; this is not a real-time-copyable timing.
Priceable coverage: 96.0% · Options excluded: 0.0%
Sector breakdown
Full portfolio 9 positions
| Type | Streak | 8Q trend | |||||
|---|---|---|---|---|---|---|---|
| ATS ATS Corporation Common Shares | $472,112,013 | 77.78% | 16,404,170 | $9,514,419 | |||
| BKD Brookdale Senior Living Inc. Common Stock | $41,445,040 | 6.83% | 2,575,826 | $10,887,463 | Up ×1 | ||
| NVRI Enviri Corporation Common Stock | $38,872,550 | 6.40% | 1,770,959 | $-49,310,246 | Down ×1 | ||
| CCO Clear Channel Outdoor Holdings, Inc. Common Stock | $23,784,730 | 3.92% | 9,828,401 | $491,420 | |||
| GRPN Groupon, Inc. - Common Stock | $15,810,885 | 2.60% | 657,144 | Up ×1 | |||
| RC Ready Capital Corporation Common Stock | $7,559,883 | 1.25% | 4,319,933 | $561,592 | |||
| JELD JELD-WEN Holding, Inc. Common Stock | $4,664,432 | 0.77% | 3,109,621 | $3,701,095 | Up ×1 | ||
| LOGCD | $2,592,935 | 0.43% | 291,341 | Up ×1 | |||
| SBNY | $180,000 | 0.03% | 400,000 | $-80,000 | |||
| No matches | |||||||
Biggest new bets
New positions opened this quarter, largest first.
| Security | Value | Shares | % of portfolio |
|---|---|---|---|
| GRPN | $15,810,885 | 657,144 | 2.60% |
| LOGCD | $2,592,935 | 291,341 | 0.43% |
Top movers (QoQ)
Exited positions
Includes corporate events (mergers, delistings) — not all exits are sells
Closed positions reflect 13F reporting changes; for index managers these are often mechanical (delisting, M&A, index rebalancing), not active decisions.
| Security | Quarter | Shares before | Value before | Price since exit |
|---|---|---|---|---|
| KVUE | Dec. 31, 2025 | 2,595,000 | $42,116,850 | 9.8% |
| SOLS | March 31, 2026 | 633,801 | $30,790,053 | -25.0% |
| PARA | June 30, 2025 | 2,027,408 | $24,247,800 | |
| JBS | March 31, 2026 | 1,306,000 | $18,832,520 | -24.9% |
| BORR | March 31, 2026 | 2,182,136 | $8,794,008 | -20.6% |
| MLAB | March 31, 2026 | 70,300 | $5,518,550 | 35.5% |
| CCIR | Sept. 30, 2025 | 325,000 | $3,565,250 | No longer tracked |
| RC | March 31, 2025 | 278,856 | $1,901,798 | -63.2% |