Institutional
MASON CAPITAL MANAGEMENT LLC
CIK 0001218735
$612.9M
Reported AUM
7
Positions
Q1 2026
Period
2026-05-15
Filed
The Brief · MASON CAPITAL MANAGEMENT LLC · Q1 2026
AI · grounded in 13F
MASON CAPITAL MANAGEMENT LLC established a new position in NVRI valued at $88.18M. The fund closed out positions in SOLS with a reduction of $30.79M, JBS at $18.83M, and BORR at $8.79M. Other activity included a new position in JELD for $963,337 and a 5.4% increase in shares of ATS.
Portfolio · Q1 2026
Top holdings
QoQ vs Q4 2025
| # | Stock | Issuer | Price | Day % | 1Y Gr. | 5Y Gr. | Value | % of book | Δ shares (QoQ) | Status |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | ATS | ATS CORPORATION | $26.92 | -4.74% | -10.68% | -10.36% | $462.6M | 75.48% | +840,602 | +5.4% |
| 2 | NVRI | ENVIRI CORP | $19.30 | -2.03% | 135.37% | -4.08% | $88.2M | 14.39% | +4,494,536 | NEW |
| 3 | BKD | BROOKDALE SENIOR LIVING INC | $12.34 | 3.78% | 84.73% | 64.10% | $30.6M | 4.99% | −1,352,200 | −37.7% |
| 4 | CCO | CLEAR CHANNEL OUTDOOR HLDGS | $2.40 | -0.41% | 110.53% | -9.77% | $23.3M | 3.80% | — | HELD |
| 5 | RC | READY CAPITAL CORP | $1.71 | -0.58% | -57.43% | -80.04% | $7.0M | 1.14% | +543,794 | +14.4% |
| 6 | JELD | JELD-WEN HOLDING INC | $1.86 | -7.92% | -51.69% | -92.98% | $963K | 0.16% | +776,885 | NEW |
| 7 | SBNY | SIGNATURE BANK | $0.44 | -2.22% | -48.24% | -78.00% | $260K | 0.04% | — | HELD |
| 8 | SOLS | SOLSTICE ADV MATERIALS INC | $81.02 | -3.70% | 77.42% | 70.24% | — | — | −633,801 | EXITED |
| 9 | JBS | JBS N.V. | $12.24 | 0.25% | -4.68% | -4.20% | — | — | −1,306,000 | EXITED |
| 10 | BORR | BORR DRILLING LTD | $4.81 | -4.75% | 149.22% | 250.72% | — | — | −2,182,136 | EXITED |
| 11 | MLAB | MESA LABORATORIES INC | $103.89 | -4.80% | 0.67% | -63.82% | — | — | −70,300 | EXITED |
Source: SEC EDGAR · accession 0001104659-26-062410. 13F discloses long positions only — shorts, foreign equities, and options are excluded.