MASON CAPITAL MANAGEMENT LLC 13F: Quarter-over-Quarter Portfolio Changes
MASON CAPITAL MANAGEMENT LLC reported a disclosed portfolio value of approximately $612.9 million in its latest SEC Form 13F-HR filing for Q1 2026, up 9.1% quarter on quarter. Over the quarter, the fund initiated 2 new positions, bought more shares in 2 holdings, trimmed 1 holding, and exited 4 positions.
MASON CAPITAL MANAGEMENT LLC's top buy was a new stake in Enviri CORP (NVRI) , equal to 14.4% of the disclosed portfolio. Its top sell was Solstice Advanced Matls INC (SOLS) . The fund exited the position completely after it had accounted for 5.5% of the previous portfolio.
New PositionsQ1 2026
Securities disclosed for the first time in Q1 2026 that were not present in the prior 13F-HR filing.
| Company | Ticker | Initial Portfolio Weight | History |
|---|---|---|---|
| ENVIRI CORP | NVRI | 14.4% | History → |
| JELD-WEN HLDG INC | JELD | 0.2% | History → |
Top BuysQ1 2026
The fund's top buys among existing positions in Q1 2026. Ranked by portfolio-weight impact, with the percentage of additional shares shown separately.
| Company | Ticker | Portfolio Weight Change | More Shares | History |
|---|---|---|---|---|
| READY CAPITAL CORP | RC | +-0.3% | +14.4% | History → |
| ATS | ATS | +-0.8% | +5.4% | History → |
Top SellsQ1 2026
The fund's top sells among positions it retained in Q1 2026. Ranked by portfolio-weight impact. Full exits are listed separately.
| Company | Ticker | Portfolio Weight Change | Shares Sold | History |
|---|---|---|---|---|
| BROOKDALE SR LIVING INC | BKD | -1.9% | 37.7% | History → |
Full ExitsQ1 2026
Positions present in the prior 13F-HR filing that no longer appear in Q1 2026.
| Company | Ticker | Last-Reported Portfolio Weight |
|---|---|---|
| SOLSTICE ADVANCED MATLS INC | SOLS | 5.5% |
| JBS N.V. | JBS | 3.4% |
| BORR DRILLING LTD | BORR | 1.6% |
| MESA LABS INC | MLAB | 1.0% |
Net Portfolio Value ChangeQ1 2026
- $0.6BPrior quarter
- $0.6BCurrent quarter
- +$0.1BNet delta
- +9.1%% change
Methodology & FAQ
How MASON CAPITAL MANAGEMENT LLC Quarterly Changes Are Computed
All deltas are sourced from sequential SEC Form 13F-HR filings for MASON CAPITAL MANAGEMENT LLC: each row joins the most recent filing against the immediately preceding quarterly filing for the same fund. Share-count changes reflect reported trading activity, while portfolio weights can also move because of market price changes. Portfolio weights are normalized to exclude listed options for comparability. A complete description — including how confidential treatment filings are handled — is documented in the Methodology.
What stocks did MASON CAPITAL MANAGEMENT LLC buy in Q1 2026?
In Q1 2026, MASON CAPITAL MANAGEMENT LLC initiated 2 new positions (ENVIRI CORP (NVRI), JELD-WEN HLDG INC (JELD)); bought more shares of READY CAPITAL CORP (RC), ATS (ATS).
What stocks did MASON CAPITAL MANAGEMENT LLC sell in Q1 2026?
In Q1 2026, MASON CAPITAL MANAGEMENT LLC fully sold 4 positions (SOLSTICE ADVANCED MATLS INC (SOLS), JBS N.V. (JBS), BORR DRILLING LTD (BORR), MESA LABS INC (MLAB)); reduced holdings in BROOKDALE SR LIVING INC (BKD).
Which positions did MASON CAPITAL MANAGEMENT LLC initiate in Q1 2026?
MASON CAPITAL MANAGEMENT LLC established 2 new positions in Q1 2026: ENVIRI CORP (NVRI, 14.4%), JELD-WEN HLDG INC (JELD, 0.2%).
Which existing positions saw the largest allocation increases for MASON CAPITAL MANAGEMENT LLC in Q1 2026?
Of 2 existing positions with share-count increases in Q1 2026, the largest were: READY CAPITAL CORP (RC, +-0.3% weight, +14.4% shares), ATS (ATS, +-0.8% weight, +5.4% shares).
Which positions did MASON CAPITAL MANAGEMENT LLC fully exit in Q1 2026?
MASON CAPITAL MANAGEMENT LLC fully exited 4 positions in Q1 2026: SOLSTICE ADVANCED MATLS INC (SOLS, last-reported weight 5.5%), JBS N.V. (JBS, last-reported weight 3.4%), BORR DRILLING LTD (BORR, last-reported weight 1.6%), MESA LABS INC (MLAB, last-reported weight 1.0%).
Which existing positions saw the largest allocation reductions for MASON CAPITAL MANAGEMENT LLC in Q1 2026?
Of 1 existing position with share-count reductions in Q1 2026, the largest were: BROOKDALE SR LIVING INC (BKD, -1.9% weight, -37.7% shares).
Do quarter-over-quarter 13F allocation changes constitute explicit trading signals?
No. Quarter-over-quarter changes reflect a combination of active trading and market price movement. A weight increase can result from price appreciation alone, without the manager adding shares. Share-count delta is the cleaner indicator of explicit trading activity. All deltas on this page are sourced from sequential SEC Form 13F-HR filings.