Mountaineer Partners Management, LLC
In its 13F for Q4 2025 (holdings as of December 31, 2025, filed February 13, 2026), Mountaineer Partners Management, LLC reported 17 stock positions worth $178.7 million. Its top holding was Century Aluminum (CENX) at 13.3% of the portfolio, followed by Hudbay Minerals (HBM, 8.7%) and Ati (ATI, 8.3%). Compared with Q3 2025, it opened 3 new positions, sold out of 4, added to 5 and reduced 9. The biggest buy was a new position in Sensient Technologies (SXT) and the biggest sale an exit from Everus Construction (ECG).
- Most Recent 13F
- Q2 2026
- Location
- New York, NY
- CIK
- 0001730532
- Portfolio Value
- $178.7M (Q4 2025)
- SEC Filing
- 0000919574-26-000943 ↗ filed Feb 13, 2026
Holdings Value
Holdings 17 stocks · $178.7M
| CENX Century Aluminum Company | 13.34% | 608,475 | $23.8M | Reduce -8.0% |
| HBM Hudbay Minerals Inc. | 8.74% | 787,247 | $15.6M | Reduce -17.6% |
| ATI Ati Inc. | 8.28% | 128,909 | $14.8M | Reduce -10.5% |
| FCX Freeport-McMoran Inc. | 7.57% | 266,327 | $13.5M | Reduce -9.4% |
| AA Alcoa Corp. | 7.20% | 241,994 | $12.9M | Reduce -18.4% |
| CSTM Constellium SE | 7.19% | 681,464 | $12.8M | Reduce -18.3% |
| CRS Carpenter Technology | 6.46% | 36,690 | $11.6M | Reduce -10.2% |
| SXT Sensient Technologies Corp. | 6.16% | 117,090 | $11.0M | New |
| SARO Standardaero Inc. | 5.90% | 367,498 | $10.5M | Add +26.4% |
| BLDR Builders Firstsource Inc. | 5.42% | 94,091 | $9.7M | Add +54.9% |
| KEX Kirby Corp. | 5.39% | 87,444 | $9.6M | Add +33.6% |
| DHI D.R. Horton Inc. | 5.24% | 65,004 | $9.4M | Add +133.2% |
| AMBP Ardagh Metal Packaging SA | 3.37% | 1,469,480 | $6.0M | Reduce -4.5% |
| NXE Nexgen Energy Ltd. | 2.77% | 538,042 | $4.9M | Reduce -4.7% |
| ULCC Frontier Group Holdings Inc. | 2.51% | 953,375 | $4.5M | New |
| SJT San Juan Basin Royalty TR | 2.30% | 732,351 | $4.1M | Add +1.9% |
| CCJ Cameco Corp. | 2.17% | 42,424 | $3.9M | New |
Portfolio Sells Q3 2025 → Q4 2025
| ECG Everus Construction Group | Sold out | 0.00% | −8.47 |
| ENTG Entegris Inc. | Sold out | 0.00% | −6.63 |
| VSH Vishay Intertechnology Inc. | Sold out | 0.00% | −6.60 |
| UEC Uranium Energy Corp. | Sold out | 0.00% | −2.49 |
| AMBP Ardagh Metal Packaging SA | Reduce -4.5% | 3.37% | −0.20 |
| NXE Nexgen Energy Ltd. | Reduce -4.7% | 2.77% | −0.17 |
| CSTM Constellium SE | Reduce -18.3% | 7.19% | −0.03 |
| HBM Hudbay Minerals Inc. | Reduce -17.6% | 8.74% | +0.32 |
| CRS Carpenter Technology | Reduce -10.2% | 6.46% | +0.63 |
| FCX Freeport-McMoran Inc. | Reduce -9.4% | 7.57% | +0.86 |
| ATI Ati Inc. | Reduce -10.5% | 8.28% | +1.46 |
| AA Alcoa Corp. | Reduce -18.4% | 7.20% | +1.52 |
| CENX Century Aluminum Company | Reduce -8.0% | 13.34% | +2.05 |
Portfolio Buys Q3 2025 → Q4 2025
| SXT Sensient Technologies Corp. | New | 6.16% | +6.16 |
| ULCC Frontier Group Holdings Inc. | New | 2.51% | +2.51 |
| DHI D.R. Horton Inc. | Add +133.2% | 5.24% | +2.49 |
| KEX Kirby Corp. | Add +33.6% | 5.39% | +2.22 |
| CCJ Cameco Corp. | New | 2.17% | +2.17 |
| SARO Standardaero Inc. | Add +26.4% | 5.90% | +1.28 |
| BLDR Builders Firstsource Inc. | Add +54.9% | 5.42% | +1.13 |
| SJT San Juan Basin Royalty TR | Add +1.9% | 2.30% | −0.22 |
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 |