MASON CAPITAL MANAGEMENT LLC
Q4 2023 Form 13-F
NEW YORK, NEW YORK
CIK 0001218735
· CRD 158797
· SEC-registered investment adviser
$893.9M Reported Value Total
MASON CAPITAL MANAGEMENT LLC reports 4 total accounts under management (AUM). There are 4 discretionary accounts valued at $1,957,596,252, and 0 non-discretionary accounts.
Source: Form ADV filed * Note that certain holdings are exempt from Form 13-F reporting, so the AUM totals may be greater than the Form 13-F total.
Private funds (Form ADV)
6 funds
· $2.8B gross asset value
Hedge Fund: $2.3B · Private Equity Fund: $509.2M
Source: Form ADV filed 2026-03-31
Reported value
$893.9M
Quarter over quarter
+1.9%
Holdings
7
Top-10 concentration
100.0%
Key People
Form ADV owners & control persons
Kenneth Mario Garschina
MANAGING MEMBER AND PRINCIPAL
Michael Emil Martino
MANAGING MEMBER AND PRINCIPAL
Daniela Constantino
ANALYST AND MANAGING MEMBER
Filing Navigation
Coverage begins with the second quarter of 2013. Earlier quarters are not shown while their accuracy is being verified.
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Q4 2023 13F record
Q4 2023 13F filing summary
| Period of report | December 31, 2023 |
|---|---|
| Filed | February 15, 2024 |
| Form | 13F-HR |
| Reported value | $893.9M |
| Positions | 7 |
| Change in reported value | -23.1% |
| New positions | 1 |
| Exited positions | 2 |
| Position turnover | 33.3% |
| Top-10 concentration | 100.0% |
13F filings by quarter
| Quarter | Positions | Value |
|---|---|---|
|
Q2 2026 13F
Filed Aug 14, 2026
|
9 | $607.0M |
|
Q1 2026 13F
Filed May 15, 2026
|
7 | $612.9M |
|
Q4 2025 13F
Filed Feb 17, 2026
|
9 | $561.6M |
|
Q3 2025 13F
Filed Nov 14, 2025
|
6 | $491.4M |
|
Q2 2025 13F
Filed Aug 14, 2025
|
4 | $511.5M |
|
Q1 2025 13F
Filed May 15, 2025
|
5 | $427.2M |
|
Q4 2024 13F
Filed Feb 14, 2025
|
4 | $470.5M |
|
Q3 2024 13F
Filed Nov 14, 2024
|
6 | $502.6M |
|
Q2 2024 13F
Filed Aug 14, 2024
|
6 | $538.2M |
|
Q1 2024 13F
Filed May 15, 2024
|
6 | $727.8M |
|
Q4 2023 13F
Filed Feb 15, 2024
|
7 | $893.9M |
|
Q3 2023 13F
Filed Nov 14, 2023
|
8 | $1.2B |
|
Q2 2023 13F
Filed Aug 14, 2023
|
10 | $1.0B |
|
Q1 2023 13F
Filed May 15, 2023
|
12 | $234.2M |
|
Q4 2022 13F
Filed Feb 14, 2023
|
12 | $609.2M |
|
Q3 2022 13F
Filed Nov 14, 2022
|
12 | $257.8M |
|
Q2 2022 13F
Filed Aug 15, 2022
|
16 | $308.6M |
|
Q1 2022 13F
Filed May 16, 2022
|
16 | $313.3M |
|
Q4 2021 13F
Filed Feb 14, 2022
|
7 | $208.9M |
|
Q3 2021 13F
Filed Nov 15, 2021
|
32 | $1.4B |
33 earlier quarters on file — choose one from the quarter menu above.
Top 7 holdings · Q4 2023
| # | Holding | Reported value | % of portfolio |
|---|---|---|---|
| 1 | ATS ATS CORPORATION | $768.8M | 86.01% |
| 2 | XLI SELECT SECTOR SPDR TR | $63.0M | 7.04% |
| 3 | B BARNES GROUP INC | $31.4M | 3.51% |
| 4 | SDRL SEADRILL 2021 LIMITED | $18.6M | 2.08% |
| 5 | CLBRU COLOMBIER ACQUIS CORP II | $7.6M | 0.85% |
| 6 | CCO CLEAR CHANNEL OUTDOOR HLDGS | $4.4M | 0.49% |
| 7 | FWP FORWARD PHARMA A/S | $210.0K | 0.02% |
Values as reported on the Q4 2023 Form 13F. Every position is in the holdings table below.