MASON CAPITAL MANAGEMENT LLC — Quarter-over-Quarter 13F Allocation Shifts Q1 2026
In Q1 2026, MASON CAPITAL MANAGEMENT LLC initiated 2 new positions, increased allocation to 2 existing positions, trimmed 1 position, and exited 4 positions entirely. The fund's 13F equity book grew from $0.56B to $0.61B (+9.1% QoQ) . All deltas are sourced from sequential SEC Form 13F-HR filings; share-count changes reflect explicit trading activity, while weight changes can also include price movement. This page lists every position change reported — the portfolio overview shows a summary of the top shifts.
Net Portfolio Value Change
- $0.56BPrior quarter
- $0.61BCurrent quarter
- + $0.05BNet delta
- +9.1%% change
New Position Initiations Q1 2026
Securities disclosed for the first time in Q1 2026 that were not present in the prior 13F-HR filing.
| Company | Ticker | Initial Allocation Weight | History |
|---|---|---|---|
| ENVIRI CORP | NVRI | 14.39% | History → |
| JELD-WEN HLDG INC | JELD | 0.16% | History → |
Largest Allocation Increases Q1 2026
Largest portfolio-weight increases in existing positions. Share-count delta is shown separately so price-only re-weighting can be distinguished from active adds.
| Company | Ticker | Δ Weight | Δ Shares | History |
|---|---|---|---|---|
| READY CAPITAL CORP | RC | +-0.32% | +14.40% | History → |
| ATS CORP | ATS | +-0.84% | +5.40% | History → |
Largest Allocation Reductions Q1 2026
Largest portfolio-weight decreases in existing positions (positions kept open at a lower allocation).
| Company | Ticker | Δ Weight | Δ Shares | History |
|---|---|---|---|---|
| BROOKDALE SR LIVING INC | BKD | -1.90% | -37.71% | History → |
Exited Positions Q1 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 | 5.48% |
| JBS N.V., CLASS A | JBS | 3.35% |
| BORR DRILLING LTD | BORR | 1.57% |
| MESA LABS INC | MLAB | 0.98% |
Methodology & FAQ
How MASON CAPITAL MANAGEMENT LLC Quarterly Changes Are Computed
Each row above is computed by joining the most recent 13F-HR filing for MASON CAPITAL MANAGEMENT LLC against the immediately preceding quarterly filing for the same fund. Portfolio weights are normalized to exclude listed options for comparability. A complete description of the methodology — including how confidential treatment filings are handled and why share count rather than weight is the cleaner trading signal — is documented in the Methodology.
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, 14.39%), JELD-WEN HLDG INC (JELD, 0.16%).
Which existing positions saw the largest allocation increases for MASON CAPITAL MANAGEMENT LLC in Q1 2026?
The largest portfolio-weight increases in existing positions were: READY CAPITAL CORP (RC, +-0.32% weight, +14.40% shares), ATS CORP (ATS, +-0.84% weight, +5.40% 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 5.48%), JBS N.V., CLASS A (JBS, last-reported weight 3.35%), BORR DRILLING LTD (BORR, last-reported weight 1.57%), MESA LABS INC (MLAB, last-reported weight 0.98%).
Which existing positions saw the largest allocation reductions for MASON CAPITAL MANAGEMENT LLC in Q1 2026?
The largest portfolio-weight reductions in positions kept open were: BROOKDALE SR LIVING INC (BKD, -1.90% weight, -37.71% 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.