Mason Capital Management LLC

In its 13F for Q4 2024 (holdings as of December 31, 2024, filed February 14, 2025), Mason Capital Management LLC reported 4 stock positions worth $470.5 million. Its top holding was Ats (ATS) at 96.6% of the portfolio, followed by Clear Channel Outdoor Holdin (CCO, 2.9%) and Ready Capital (RC, 0.4%). Compared with Q3 2024, it sold out of 2 and reduced 1. The biggest sale was an exit from Veradigm (MDRX).

Most Recent 13F
Q2 2026
Location
NEW YORK, NY
CIK
0001218735
Portfolio Value
$470.5M (Q4 2024)
SEC Filing
0001104659-25-014023 ↗ filed Feb 14, 2025

Holdings Value

0$200.0M$400.0M$600.0M$800.0M Q1 2024: $727.8M Q1 2024 Q2 2024: $538.2M Q2 2024 Q3 2024: $502.6M Q3 2024 Q4 2024: $470.5M $470.5M Q4 2024 Q1 2025: $427.2M Q1 2025 Q2 2025: $511.5M Q2 2025 Q3 2025: $491.4M Q3 2025 Q4 2025: $561.6M Q4 2025 Q1 2026: $612.9M Q1 2026 Q2 2026: $607.0M Q2 2026

Holdings 4 stocks · $470.5M
ATS Ats Corp. 96.62% 14,914,765 $454.6M No change
CCO Clear Channel Outdoor Holdin 2.86% 9,828,401 $13.5M No change
RC Ready Capital Corp. 0.40% 278,856 $1.9M Reduce -66.8%
SBNY Signature Bank 0.12% 400,000 $548K No change

Portfolio Sells Q3 2024 → Q4 2024
MDRX Veradigm Inc. Sold out 0.00% −4.82
BARNES GROUP INC Sold out 0.00% −4.41
RC Ready Capital Corp. Reduce -66.8% 0.40% −0.87

Portfolio Buys Q3 2024 → Q4 2024
None this quarter.

All Filings

QuarterPositions13F Reported ValueTop Holdings
Q2 2026 9$607.0MATS, BKD, NVRI, CCO, GRPN
Q1 2026 7$612.9MATS, NVRI, BKD, CCO, RC
Q4 2025 9$561.6MATS, BKD, SOLS, CCO, JBS
Q3 2025 6$491.4MATS, KVUE, BKD, CCO, MLAB
Q2 2025 4$511.5MATS, CCO, CCIR, SBNY
Q1 2025 5$427.2MATS, PARAA, CCO, CCIR, SBNY
Q4 2024 4$470.5MATS, CCO, RC, SBNY
Q3 2024 6$502.6MATS, MDRX, BARNES GROUP INC, CCO, RC
Q2 2024 6$538.2MATS, BARNES GROUP INC, CCO, MDRX, IIIV
Q1 2024 6$727.8MATS, BARNES GROUP INC, SDRL, CCO, MDRX