Mountaineer Partners Management, LLC
In its 13F for Q3 2025 (holdings as of September 30, 2025, filed November 14, 2025), Mountaineer Partners Management, LLC reported 18 stock positions worth $171.9 million. Its top holding was Century Aluminum (CENX) at 11.3% of the portfolio, followed by Everus Construction (ECG, 8.5%) and Hudbay Minerals (HBM, 8.4%). Compared with Q2 2025, it opened 2 new positions, added to 3 and reduced 8. The biggest buy was a new position in D.R. Horton (DHI) and the biggest sale Vishay Intertechnology (VSH, shares −0%).
- Most Recent 13F
- Q2 2026
- Location
- New York, NY
- CIK
- 0001730532
- Portfolio Value
- $171.9M (Q3 2025)
- SEC Filing
- 0000919574-25-006893 ↗ filed Nov 14, 2025
Holdings Value
Holdings 18 stocks · $171.9M
| CENX Century Aluminum Company | 11.29% | 661,043 | $19.4M | Reduce -6.3% |
| ECG Everus Construction Group | 8.47% | 169,844 | $14.6M | Reduce -17.6% |
| HBM Hudbay Minerals Inc. | 8.42% | 955,419 | $14.5M | Reduce -15.0% |
| CSTM Constellium SE | 7.22% | 833,776 | $12.4M | Reduce -1.4% |
| ATI Ati Inc. | 6.81% | 144,020 | $11.7M | Add +17.1% |
| FCX Freeport-McMoran Inc. | 6.71% | 294,049 | $11.5M | Add +16.2% |
| ENTG Entegris Inc. | 6.63% | 123,234 | $11.4M | Reduce -2.4% |
| VSH Vishay Intertechnology Inc. | 6.60% | 742,177 | $11.4M | Reduce -0.0% |
| CRS Carpenter Technology | 5.83% | 40,849 | $10.0M | Add +2.2% |
| AA Alcoa Corp. | 5.67% | 296,642 | $9.8M | Reduce -2.7% |
| SARO Standardaero Inc. | 4.61% | 290,730 | $7.9M | No change |
| BLDR Builders Firstsource Inc. | 4.28% | 60,759 | $7.4M | Reduce -2.7% |
| AMBP Ardagh Metal Packaging SA | 3.57% | 1,538,484 | $6.1M | No change |
| KEX Kirby Corp. | 3.18% | 65,431 | $5.5M | No change |
| NXE Nexgen Energy Ltd. | 2.94% | 564,507 | $5.1M | No change |
| DHI D.R. Horton Inc. | 2.75% | 27,876 | $4.7M | New |
| SJT San Juan Basin Royalty TR | 2.53% | 719,054 | $4.3M | No change |
| UEC Uranium Energy Corp. | 2.49% | 320,952 | $4.3M | New |
Portfolio Sells Q2 2025 → Q3 2025
| VSH Vishay Intertechnology Inc. | Reduce -0.0% | 6.60% | −1.19 |
| BLDR Builders Firstsource Inc. | Reduce -2.7% | 4.28% | −0.53 |
| AA Alcoa Corp. | Reduce -2.7% | 5.67% | −0.27 |
| CSTM Constellium SE | Reduce -1.4% | 7.22% | −0.22 |
| ECG Everus Construction Group | Reduce -17.6% | 8.47% | −0.19 |
| ENTG Entegris Inc. | Reduce -2.4% | 6.63% | −0.10 |
| HBM Hudbay Minerals Inc. | Reduce -15.0% | 8.42% | +0.54 |
| CENX Century Aluminum Company | Reduce -6.3% | 11.29% | +2.89 |
Portfolio Buys Q2 2025 → Q3 2025
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 |