Mountaineer Partners Management, LLC — 13F Holdings & Portfolio
CIK 1730532 · latest 13F-HR filed 2026-05-15
Mountaineer Partners Management, LLC manages $201.3M in 13F-reported U.S. long-equity assets across 32 reported positions as of its 2026-03-31 13F-HR filing. Its largest disclosed positions are CENX (15.84%), CSTM (6.97%), AA (6.59%). Quarter over quarter (versus its 2025-12-31 filing) the fund opened 1 new position, exited 2, added to 8, and trimmed 4.
AUM is the long-equity portion reported on Form 13F-HR. Excludes short positions, cash, foreign holdings, and non-13F assets. For informational purposes only — not investment advice.
$201.3M
Long-equity book
32
Distinct positions
2026-03-31
Filed 2026-05-15
+1 / −2 / ↑8 / ↓4
vs 2025-12-31
| Name | Title / Status | Ownership | Type |
|---|
Top Adds (vs prior quarter)
- CENTURY ALUM CO$10.4M +43.8%
- CONSTELLIUM SE$3.3M +26.0%
- ALCOA CORP$2.6M +20.5%
- CARPENTER TECHNOLOGY CORP$2.6M +22.6%
- SENSIENT TECHNOLOGIES CORP$2.5M +23.0%
Top Trims
- BUILDERS FIRSTSOURCE INC-$1.6M -16.5%
- ATI INC-$1.4M -9.8%
- FRONTIER GROUP HLDGS INC-$1.1M -25.1%
- HUDBAY MINERALS INC-$870.6K -5.6%
Rows tagged Call or Put are options positions, not stock. Per SEC Form 13F-HR, Value shows the notional value of the underlying (shares covered × underlying price), not the option premium. Shares is the number of underlying shares covered (divide by 100 for contract count).
| # | Issuer | Symbol | CUSIP | Value | Weight | Shares | Type |
|---|---|---|---|---|---|---|---|
| 1 | CENTURY ALUM CO | CENX | 156431108 | $31.9M | 15.84% | 543,211 | SH |
| 2 | CONSTELLIUM SE | CSTM | F21107101 | $14.0M | 6.97% | 571,225 | SH |
| 3 | ALCOA CORP | AA | 013872106 | $13.3M | 6.59% | 200,130 | SH |
| 4 | HUDBAY MINERALS INC | HBM | 443628102 | $12.4M | 6.18% | 594,845 | SH |
| 5 | FREEPORT MCMORAN INC | FCX | 35671D857 | $12.1M | 6.00% | 205,508 | SH |
| 6 | CARPENTER TECHNOLOGY CORP | CRS | 144285103 | $12.0M | 5.96% | 30,433 | SH |
| 7 | SENSIENT TECHNOLOGIES CORP | SXT | 81725T100 | $11.4M | 5.65% | 131,646 | SH |
| 8 | ATI INC | ATI | 01741R102 | $11.2M | 5.57% | 77,072 | SH |
| 9 | KIRBY CORP | KEX | 497266106 | $9.7M | 4.81% | 72,915 | SH |
| 10 | STANDARDAERO INC | SARO | 85423L103 | $8.5M | 4.23% | 330,014 | SH |
| 11 | HARMONY GOLD MNG LTD | HMY | 413216300 | $8.3M | 4.12% | 540,042 | SH |
| 12 | D R HORTON INC | DHI | 23331A109 | $7.4M | 3.65% | 53,585 | SH |
| 13 | BUILDERS FIRSTSOURCE INC | BLDR | 12008R107 | $6.6M | 3.29% | 80,443 | SH |
| 14 | ARDAGH METAL PACKAGING S A | AMBP | L02235106 | $6.1M | 3.04% | 1,511,272 | SH |
| 15 | CAMECO CORP | CCJ | 13321L108 | $3.6M | 1.80% | 33,307 | SH |
| 16 | FRONTIER GROUP HLDGS INC | ULCC | 35909R108 | $2.6M | 1.31% | 747,181 | SH |
| 17 | CENTURY ALUM CO | CENX | 156431108 | $2.4M | 1.19% | 40,786 | SH |
| 18 | HUDBAY MINERALS INC | HBM | 443628102 | $2.3M | 1.15% | 111,195 | SH |
| 19 | ALCOA CORP | AA | 013872106 | $2.2M | 1.11% | 33,557 | SH |
| 20 | CARPENTER TECHNOLOGY CORP | CRS | 144285103 | $2.2M | 1.08% | 5,496 | SH |
| 21 | SENSIENT TECHNOLOGIES CORP | SXT | 81725T100 | $2.2M | 1.07% | 24,938 | SH |
| 22 | CONSTELLIUM SE | CSTM | F21107101 | $2.1M | 1.07% | 87,265 | SH |
| 23 | ATI INC | ATI | 01741R102 | $2.1M | 1.06% | 14,712 | SH |
| 24 | KIRBY CORP | KEX | 497266106 | $2.1M | 1.06% | 16,102 | SH |
| 25 | FREEPORT MCMORAN INC | FCX | 35671D857 | $2.1M | 1.04% | 35,465 | SH |
| 26 | STANDARDAERO INC | SARO | 85423L103 | $2.0M | 0.99% | 77,421 | SH |
| 27 | HARMONY GOLD MNG LTD | HMY | 413216300 | $1.9M | 0.97% | 126,693 | SH |
| 28 | D R HORTON INC | DHI | 23331A109 | $1.8M | 0.88% | 12,956 | SH |
| 29 | ARDAGH METAL PACKAGING S A | AMBP | L02235106 | $1.5M | 0.74% | 366,810 | SH |
| 30 | BUILDERS FIRSTSOURCE INC | BLDR | 12008R107 | $1.5M | 0.73% | 17,760 | SH |
| 31 | CAMECO CORP | CCJ | 13321L108 | $990.2K | 0.49% | 9,117 | SH |
| 32 | FRONTIER GROUP HLDGS INC | ULCC | 35909R108 | $727.9K | 0.36% | 206,194 | SH |
| Period | Filed | AUM | Holdings | Accession |
|---|---|---|---|---|
| 2026-03-31 | 2026-05-15 | $201.3M | 32 | 0000919574-26-003280 |
| 2025-12-31 | 2026-02-13 | $178.7M | 34 | 0000919574-26-000943 |
| 2025-09-30 | 2025-11-14 | $171.9M | 36 | 0000919574-25-006893 |