Mountaineer Partners Management, LLC
In its 13F for Q1 2026 (holdings as of March 31, 2026, filed May 15, 2026), Mountaineer Partners Management, LLC reported 16 stock positions worth $201.3 million. Its top holding was Century Aluminum (CENX) at 17.0% of the portfolio, followed by Constellium (CSTM, 8.0%) and Alcoa (AA, 7.7%). Compared with Q4 2025, it opened 1 new position, sold out of 2, added to 6 and reduced 7. The biggest buy was a new position in Harmony Gold MNG-Spon ADR (HMY) and the biggest sale an exit from Nexgen Energy (NXE).
- Most Recent 13F
- Q2 2026
- Location
- New York, NY
- CIK
- 0001730532
- Portfolio Value
- $201.3M (Q1 2026)
- SEC Filing
- 0000919574-26-003280 ↗ filed May 15, 2026
Holdings Value
Holdings 16 stocks · $201.3M
| CENX Century Aluminum Company | 17.02% | 583,997 | $34.3M | Reduce -4.0% |
| CSTM Constellium SE | 8.04% | 658,490 | $16.2M | Reduce -3.4% |
| AA Alcoa Corp. | 7.70% | 233,687 | $15.5M | Reduce -3.4% |
| HBM Hudbay Minerals Inc. | 7.33% | 706,040 | $14.8M | Reduce -10.3% |
| FCX Freeport-McMoran Inc. | 7.04% | 240,973 | $14.2M | Reduce -9.5% |
| CRS Carpenter Technology | 7.03% | 35,929 | $14.2M | Reduce -2.1% |
| SXT Sensient Technologies Corp. | 6.72% | 156,584 | $13.5M | Add +33.7% |
| ATI Ati Inc. | 6.63% | 91,784 | $13.4M | Reduce -28.8% |
| KEX Kirby Corp. | 5.88% | 89,017 | $11.8M | Add +1.8% |
| SARO Standardaero Inc. | 5.23% | 407,435 | $10.5M | Add +10.9% |
| HMY Harmony Gold MNG-Spon ADR | 5.09% | 666,735 | $10.2M | New |
| DHI D.R. Horton Inc. | 4.54% | 66,541 | $9.1M | Add +2.4% |
| BLDR Builders Firstsource Inc. | 4.02% | 98,203 | $8.1M | Add +4.4% |
| AMBP Ardagh Metal Packaging SA | 3.78% | 1,878,082 | $7.6M | Add +27.8% |
| CCJ Cameco Corp. | 2.29% | 42,424 | $4.6M | No change |
| ULCC Frontier Group Holdings Inc. | 1.67% | 953,375 | $3.4M | No change |
Portfolio Sells Q4 2025 → Q1 2026
| NXE Nexgen Energy Ltd. | Sold out | 0.00% | −2.77 |
| SJT San Juan Basin Royalty TR | Sold out | 0.00% | −2.30 |
| ATI Ati Inc. | Reduce -28.8% | 6.63% | −1.65 |
| HBM Hudbay Minerals Inc. | Reduce -10.3% | 7.33% | −1.41 |
| FCX Freeport-McMoran Inc. | Reduce -9.5% | 7.04% | −0.53 |
| AA Alcoa Corp. | Reduce -3.4% | 7.70% | +0.50 |
| CRS Carpenter Technology | Reduce -2.1% | 7.03% | +0.57 |
| CSTM Constellium SE | Reduce -3.4% | 8.04% | +0.85 |
| CENX Century Aluminum Company | Reduce -4.0% | 17.02% | +3.69 |
Portfolio Buys Q4 2025 → Q1 2026
| HMY Harmony Gold MNG-Spon ADR | New | 5.09% | +5.09 |
| SXT Sensient Technologies Corp. | Add +33.7% | 6.72% | +0.57 |
| KEX Kirby Corp. | Add +1.8% | 5.88% | +0.48 |
| AMBP Ardagh Metal Packaging SA | Add +27.8% | 3.78% | +0.41 |
| SARO Standardaero Inc. | Add +10.9% | 5.23% | −0.67 |
| DHI D.R. Horton Inc. | Add +2.4% | 4.54% | −0.70 |
| BLDR Builders Firstsource Inc. | Add +4.4% | 4.02% | −1.40 |
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 |