Mason Capital Management Llc
- Regulatory AUM
- $2.2B
- Discretionary
- $1.7B
- Clients
- 5
- Avg AUM / client
- $447M
- Accounts
- 5
- Employees
- 15
AUM over time
Reported AUM from Form ADV filings, plotted by filing date · as of Mar 31, 2026
Investments (13F portfolio — 7 positions, $612,852,905)
13F period Mar 31, 2026| # | Issuer | Class | Value | Shares | % of 13F | % of AUM |
|---|---|---|---|---|---|---|
| 1 | Ats Corporation | COM | $462,597,594 | 16,404,170 | 75.5% | 20.7% |
| 2 | Enviri Corp | COM | $88,182,796 | 4,494,536 | 14.4% | 3.94% |
| 3 | Brookdale Senior Living Inc | COM | $30,557,577 | 2,233,741 | 4.99% | 1.37% |
| 4 | Clear Channel Outdoor Hldgs | COM | $23,293,310 | 9,828,401 | 3.8% | 1.04% |
| 5 | Ready Capital Corp | REIT | $6,998,291 | 4,319,933 | 1.14% | 0.31% |
| 6 | Jeld Wen Holding Inc | COM | $963,337 | 776,885 | 0.16% | 0.04% |
| 7 | Signature Bank | COM | $260,000 | 400,000 | 0.04% | 0.01% |
Top 25 of 7 positions from the manager's latest Form 13F · source filing (EDGAR) ↗. 13F covers long US-listed positions only. "% of AUM" is share of the firm's total regulatory AUM (Form ADV Item 5.F).
Who they serve
| Client type | Clients | AUM | % of AUM |
|---|---|---|---|
| Pooled investment vehicles (non-investment companies) | 5 | $2.2B | 100.0% |
Private funds (2)
Reported in Form ADV Section 7.B.(1), filing of Mar 2024 · $2.0B combined gross assets
| Fund | Type | Domicile | Gross assets | Owners |
|---|---|---|---|---|
| Mason Capital Master Fund, Lp master | Hedge Fund | Cayman Islands | $2.0B | 53 |
| Mason Capital Spv Iii, Llc | Hedge Fund | Delaware | $7.9K | 1 |
People (7)
| Name | Role / title | Credentials | With firm since | Ownership |
|---|---|---|---|---|
| Garschina, Kenneth, Mario | Managing Member And Principal | Jun 2000 (26y) | 50% – 75% | |
| Martino, Michael, Emil | Managing Member And Principal | Jun 2000 (26y) | 50% – 75% | |
| Grizzetti, John, Christopher | Chief Operating Officer And Managing Member | Sep 2002 (24y) | Less than 5% | |
| Satzinger, Derek, Ryan | Chief Financial Officer | Jan 2013 (14y) | Less than 5% | |
| Constantino, Daniela | Analyst And Managing Member | Dec 2013 (13y) | Less than 5% | |
| Cutini, Michael, George | General Counsel And Chief Compliance Officer | Mar 2022 (4y) | Less than 5% | |
| Read, Samuel, Thornton | Analyst And Managing Member | Jan 2023 (4y) | Less than 5% |
Entity owners (Schedule A/B)
| Entity | Title / status | Since | Sch. | Ownership |
|---|---|---|---|---|
| Mason Capital Holdings Lp | Managing Member | Oct 2009 | A | Less than 5% |
| Mason Management Holdings Llc | General Partner | Oct 2009 | B | GP / trustee / elected manager of Mason Capital Holdings Lp (indirect) |
Roster from the IAPD representatives feed; ownership and acquisition dates from Form ADV Schedule A/B. "Since" is the earliest filed registration or acquisition date.
Private funds (2, $2.0B gross assets)
| Fund | Type | Gross assets | Min. investment | Owners |
|---|---|---|---|---|
| Mason Capital Master Fund, Lp | Hedge Fund | $2.0B | $1.0M | 53 |
| Mason Capital Spv Iii, Llc | Hedge Fund | $7.9K | $1.0M | 1 |
From Form ADV Section 7.B private fund reporting.
Documents (1 archived)
| Form | Period | Size | |
|---|---|---|---|
| Form ADV (full filing) | 03/31/2026 | 1.65 MB | View · PDF · Source ↗ |
Archived copies of the firm's regulatory filings, versioned by content hash.
Disciplinary disclosures
No disciplinary events reported on the firm's latest Form ADV filing.
How they charge
- • Percentage of assets under management
- • Performance-based fees
- • Other fees
- • ONE-TIME EQUITY GRANT FROM PRIVATELY HELD PORTFOLIO COMPANY
Services
- • Portfolio management for pooled investment vehicles
Custody
Firm reports having custody of client funds or securities (Item 9.A).
No custodian data reported or mined yet.
Source
All data on this page comes from this firm's Form ADV filings, reproduced without modification. Latest filing: Mar 31, 2026.
View current Form ADV (SEC/IAPD) ↗