MASON CAPITAL MANAGEMENT LLC

NEW YORK, NY · CIK 1218735 · 13F filing filed 2026-08-14

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)

$607.0m reported value -1.0% vs Q1 2026

9positions

100.0%in top 10

2 new 2 added 1 reduced 0 sold out vs Q1 2026

Holdings, Q2 2026

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

#	Security	Ticker	Shares	Value	% of portfolio	Change	Shares change
1	ATS CORPORATION COM ATS	ATS	16,404,170	$472.1m77.78%	77.78%	Unchanged
2	BROOKDALE SR LIVING INC COM BKD	BKD	2,575,826	$41.4m6.83%	6.83%	Added +342.1k	+342,085 15.3%
3	ENVIRI CORP COM COM		1,770,959	$38.9m6.40%	6.40%	Reduced -2.7m	-2,723,577 -60.6%
4	CLEAR CHANNEL OUTDOOR HLDGS COM CCO	CCO	9,828,401	$23.8m3.92%	3.92%	Unchanged
5	GROUPON INC COM NEW GRPN	GRPN	657,144	$15.8m2.60%	2.60%	New
6	READY CAPITAL CORP COM RC	RC	4,319,933	$7.6m1.25%	1.25%	Unchanged
7	JELD-WEN HLDG INC COM JELD	JELD	3,109,621	$4.7m0.77%	0.77%	Added +2.3m	+2,332,736 300.3%
8	CONTEXTLOGIC HOLDINGS INC COMMON STOCK LOGC	LOGC	291,341	$2.6m0.43%	0.43%	New
9	SIGNATURE BK NEW YORK N Y COM SBNY	SBNY	400,000	$180.0k0.03%	0.03%	Unchanged

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