Mountaineer Partners Management, LLC
In its 13F for Q2 2026 (holdings as of June 30, 2026, filed August 13, 2026), Mountaineer Partners Management, LLC reported 11 stock positions worth $137.5 million. Its top holding was Century Aluminum (CENX) at 16.8% of the portfolio, followed by Sensient Technologies (SXT, 11.8%) and Constellium (CSTM, 11.2%). Compared with Q1 2026, it opened 1 new position, sold out of 6, added to 1 and reduced 9. The biggest buy was a new position in Middleby (MIDD) and the biggest sale an exit from Hudbay Minerals (HBM).
- Most Recent 13F
- Q2 2026
- Location
- New York, NY
- CIK
- 0001730532
- Portfolio Value
- $137.5M (Q2 2026)
- SEC Filing
- 0000919574-26-005107 ↗ filed Aug 13, 2026
Holdings Value
Holdings 11 stocks · $137.5M
| CENX Century Aluminum Company | 16.84% | 503,309 | $23.2M | Reduce -13.8% |
| SXT Sensient Technologies Corp. | 11.81% | 131,727 | $16.2M | Reduce -15.9% |
| CSTM Constellium SE | 11.18% | 482,130 | $15.4M | Reduce -26.8% |
| SARO Standardaero Inc. | 10.11% | 464,595 | $13.9M | Add +14.0% |
| CRS Carpenter Technology | 9.37% | 20,894 | $12.9M | Reduce -41.9% |
| ATI Ati Inc. | 8.66% | 60,419 | $11.9M | Reduce -34.2% |
| MIDD Middleby Corp. | 8.45% | 67,536 | $11.6M | New |
| AA Alcoa Corp. | 7.89% | 208,165 | $10.9M | Reduce -10.9% |
| HMY Harmony Gold MNG-Spon ADR | 6.78% | 612,949 | $9.3M | Reduce -8.1% |
| AMBP Ardagh Metal Packaging SA | 5.94% | 1,722,234 | $8.2M | Reduce -8.3% |
| CCJ Cameco Corp. | 2.96% | 39,903 | $4.1M | Reduce -5.9% |
Portfolio Sells Q1 2026 → Q2 2026
| HBM Hudbay Minerals Inc. | Sold out | 0.00% | −7.33 |
| FCX Freeport-McMoran Inc. | Sold out | 0.00% | −7.04 |
| KEX Kirby Corp. | Sold out | 0.00% | −5.88 |
| DHI D.R. Horton Inc. | Sold out | 0.00% | −4.54 |
| BLDR Builders Firstsource Inc. | Sold out | 0.00% | −4.02 |
| ULCC Frontier Group Holdings Inc. | Sold out | 0.00% | −1.67 |
| CENX Century Aluminum Company | Reduce -13.8% | 16.84% | −0.18 |
| AA Alcoa Corp. | Reduce -10.9% | 7.89% | +0.20 |
| CCJ Cameco Corp. | Reduce -5.9% | 2.96% | +0.67 |
| HMY Harmony Gold MNG-Spon ADR | Reduce -8.1% | 6.78% | +1.69 |
| ATI Ati Inc. | Reduce -34.2% | 8.66% | +2.03 |
| AMBP Ardagh Metal Packaging SA | Reduce -8.3% | 5.94% | +2.16 |
| CRS Carpenter Technology | Reduce -41.9% | 9.37% | +2.34 |
| CSTM Constellium SE | Reduce -26.8% | 11.18% | +3.14 |
| SXT Sensient Technologies Corp. | Reduce -15.9% | 11.81% | +5.09 |
Portfolio Buys Q1 2026 → Q2 2026
All Filings
| Quarter | Positions | 13F Reported Value | Top Holdings |
|---|---|---|---|
| Q2 2026Amended | 11 | $137.5M | CENX, SXT, CSTM, SARO, CRS |
| Q1 2026 | 16 | $201.3M | CENX, CSTM, AA, HBM, FCX |
| Q4 2025 | 17 | $178.7M | CENX, HBM, ATI, FCX, AA |
| Q3 2025 | 18 | $171.9M | CENX, ECG, HBM, CSTM, ATI |
| Q2 2025 | 16 | $151.3M | ECG, CENX, HBM, VSH, CSTM |
| Q1 2025 | 14 | $104.5M | CENX, VSH, FCX, ATI, HBM |
| Q4 2024 | 17 | $136.6M | CENX, ECG, ATI, ENTG, AA |
| Q3 2024Amended | 15 | $160.4M | CENX, VSH, FCX, ENTG, BLDR |
| Q2 2024 | 16 | $192.2M | VSH, CENX, FCX, ATI, FANG |
| Q1 2024 | 16 | $216.6M | VSH, CENX, MTRN, FCX, FANG |