MASON CAPITAL MANAGEMENT LLC — 13F Holdings

2026 Q1  ·  11 Positions

2026 Q1 Portfolio Activity

In 2026 Q1, MASON CAPITAL MANAGEMENT LLC maintained a portfolio of 11 distinct positions. The most significant new addition was ENVIRI CORP, now representing 14.39% of the total fund value. They heavily accumulated shares in READY CAPITAL CORP, increasing the position by 14.4%. Conversely, MASON CAPITAL MANAGEMENT LLC completely exited their position in SOLSTICE ADV MATERIALS INC.
Position History hover any row below to update
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PCA Score Concentration Risk
Risk ENB
Total Positions
11
Quarter
2026 Q1
Top Holding
ATS (75.5%)
Top 10 Concentration
100.0%
Turnover Rate
23.4%
Sector HHI
0.18
Items per page:
Showing 1-11 of 11

MASON CAPITAL MANAGEMENT LLC Full Holdings List — 2026 Q1

Stock History Sector / Type Port % Prev % Rank / Prev Conviction
Freshness
Change % Change Influence Shares Mkt Value Avg Cost Price Held 1st Owned Source Source Date Date Reported
ATS
ATS CORPORATION
Industrials 75.48% 76.32% #1
Prev: #1
8.0
840,602 5.4%
P
S
16,404,170 $462,597,594
$44.16 -23.6%
$28.20 +19.7%
2023 Q2 13F Filing 2026-03-31 2026-05-15
NVRI
ENVIRI CORP
Industrials 14.39% #2
Prev: #—
9.0
4,494,536
NEW
4,494,536 $88,182,796 2026 Q1 13F Filing 2026-03-31 2026-05-15
BKD
BROOKDALE SENIO...
Healthcare 4.99% 6.89% #3 1
Prev: #2
3.0
-1,352,200 -37.7%
P
S
2,233,741 $30,557,577 2025 Q3 13F Filing 2026-03-31 2026-05-15
CCO
CLEAR CHANNEL O...
Communication Services 3.80% 3.87% #4
Prev: #4
3.0
no change no change
P
S
9,828,401 $23,293,310 2019 Q2 13F Filing 2026-03-31 2026-05-15
RC
READY CAPITAL C...
Real Estate 1.14% 1.47% #5 2
Prev: #7
3.0
543,794 14.4%
P
S
4,319,933 $6,998,291 2024 Q3 13F Filing 2026-03-31 2026-05-15
JELD
JELD-WEN HOLDIN...
Industrials 0.16% #6
Prev: #—
3.6
776,885
NEW
776,885 $963,337 2026 Q1 13F Filing 2026-03-31 2026-05-15
SBNY
SIGNATURE BANK
Financial Services 0.04% 0.07% #7 2
Prev: #9
1.0
no change no change
P
S
400,000 $260,000 2024 Q1 13F Filing 2026-03-31 2026-05-15
MLAB
MESA LABORATORI...
Technology 0.00% 0.98%
Sold All 😨
(Was: #8)
0.0
-70,300 -100.0%
CLOSED
$— 2025 Q3 13F Filing 2026-03-31 2026-05-15
BORR
BORR DRILLING L...
Energy 0.00% 1.57%
Sold All 😨
(Was: #6)
0.0
-2,182,136 -100.0%
CLOSED
$— 2025 Q4 13F Filing 2026-03-31 2026-05-15
N/A
JBS N.V.
Unknown 0.00% 3.35%
Sold All 😨
(Was: #5)
0.0
-1,306,000 -100.0%
CLOSED
$— 13F Filing 2026-03-31 2026-05-15
SOLS
SOLSTICE ADV MA...
Basic Materials 0.00% 5.48%
Sold All 😨
(Was: #3)
0.0
-633,801 -100.0%
CLOSED
$— 2025 Q4 13F Filing 2026-03-31 2026-05-15
Showing 1-11 of 11 holdings

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