MASON CAPITAL MANAGEMENT LLC

NEW YORK, NY · CIK 1218735 · 13F filing filed 2025-08-14

SEC-registered investment adviser since 2012 · limited liability company

Assets managed$2.2bn
Staff15 · 10 in investment roles
Main clients (by assets)Private funds 100%
Private funds3 (2 hedge) · $2.8bn gross assets
Websitemasoncap.com
Form ADV · 2026-03-31SEC adviser record

Legal entityMASON CAPITAL MANAGEMENT LLC (US)

$511.5m reported value +19.7% vs Q1 2025

4positions

100.0%in top 10

0 new 0 added 0 reduced 1 sold out vs Q1 2025

Holdings, Q2 2025

The small lines show how much was held over the last 4 quarters (adjusted for stock splits).

#	Security	Ticker	Shares	Value	% of portfolio	Change
1	ATS CORPORATION COM ATS	ATS	15,563,568	$496.2m97.00%	97.00%	Unchanged
2	CLEAR CHANNEL OUTDOOR HLDGS COM CCO	CCO	9,828,401	$11.5m2.25%	2.25%	Unchanged
3	COHEN CIRCLE ACQUISITION COR SHS CL A CCIR	CCIR	325,000	$3.6m0.70%	0.70%	Unchanged
4	SIGNATURE BK NEW YORK N Y COM SBNY	SBNY	400,000	$300.0k0.06%	0.06%	Unchanged

Sold out since Q1 2025

Security	Ticker	Shares held before	Value then
PARAMOUNT GLOBAL		2,027,408	$24.2m2.0m shares

Stakes above 5%

Companies where this manager has reported owning more than 5% of a class of shares, on Schedule 13D (may seek influence) or 13G (passive): its latest filing for each, from 19 Dec 2024 on.

Company	Ticker	Stake	Change	Schedule	Last filed
VERADIGM INC MDRX · 13G · filed 2026-01-29	MDRX	5.8%	new	13G	2026-01-29
JELD-WEN HLDG INC JELD · 13G · filed 2026-08-05	JELD	5.5%≈ $7.2m	new	13G	2026-08-05