MASON CAPITAL MANAGEMENT LLC
CIK 0001218735 · NEW YORK, NY · Quarter end: 2026-06-30 · Filed on: 2026-08-14 · Open the SEC source ↗
MASON CAPITAL MANAGEMENT LLC reported 9 positions worth $607.0M as of June 30, 2026 (13F filed August 14, 2026). Largest holding: ATS (77.8%).
Portfolio Value (AUM)Total value of the fund's US stock portfolio reported to the SEC.
$607.0M
2026 Q2
Positions
9
Top-10 ConcentrationHow much of the portfolio sits in the 10 largest holdings. High = concentrated bets.
100.0%
Est. Net Flow (Q)
—
2026 Q2
9 positions shown
| # | Symbol | Company | Type | Value ↓ | % Port. | Shares | 1Y | YTD |
|---|---|---|---|---|---|---|---|---|
| ▸ 1 | ATS | SH | $472.1M | 77.78% | 16,404,170 | — | — | |
| ▸ 2 | BKD | SH | $41.4M | 6.83% | 2,575,826 | — | — | |
| ▸ 3 | HA7 | SH | $38.9M | 6.40% | 1,770,959 | — | — | |
| ▸ 4 | CCO | SH | $23.8M | 3.92% | 9,828,401 | — | — | |
| ▸ 5 | GRPN | SH | $15.8M | 2.60% | 657,144 | — | — | |
| ▸ 6 | RC | SH | $7.6M | 1.25% | 4,319,933 | — | — | |
| ▸ 7 | JELD | SH | $4.7M | 0.77% | 3,109,621 | — | — | |
| ▸ 8 | LOGC | SH | $2.6M | 0.43% | 291,341 | — | — | |
| ▸ 9 | SBNY | SH | $180.0K | 0.03% | 400,000 | — | — |
Read the 2026-Q2 quarterly report · 13F Filing Calendar
Frequently Asked Questions
What stocks does MASON CAPITAL MANAGEMENT LLC hold as of Q2 2026?
MASON CAPITAL MANAGEMENT LLC reported 9 positions worth $607.0M in its Q2 2026 13F filing. Largest positions: ATS (77.8%), BKD (6.8%), HA7 (6.4%), CCO (3.9%) and GRPN (2.6%).
What did MASON CAPITAL MANAGEMENT LLC buy in Q2 2026?
No previous quarter is available yet; the comparison appears with the next filing.
What did MASON CAPITAL MANAGEMENT LLC sell in Q2 2026?
No previous quarter is available yet.
13F data shows quarter-end positions, is delayed by up to 45 days and covers only long positions in US-listed securities; short positions, most derivatives and non-US assets are not reported.