Skip to content
Disclosery

Mountaineer Partners Management, LLC

Follow

13F filer, CIK 1730532, New York, NY

Mountaineer Partners Management, LLC reported $171,947,303 across 18 holdings for the quarter ended 2025-09-30, in a 13F-HR filed 2025-11-14. Its ten largest share positions make up 73.65% of the portfolio.

Filed (acceptance time not in the bulk data set), ingested 13F-HR 0000919574-25-006893

Period
2025-09-30
Reported value
$172M
Holdings
18
Top 10 weight
73.65%
New
2
Sold out
0

Largest buys vs the previous quarter

SecurityShares changeApprox. value
DHInew+27,876$4.72M
UECnew+320,952$4.28M
ATIadded+21,050$1.71M
FCXadded+41,088$1.61M
CRSadded+867$213K

Ranked by the share change valued at this quarter's implied price (value over shares in the 13F). A position sold out is valued at the previous quarter's price, its last report.

Largest sells vs the previous quarter

SecurityShares changeApprox. value
ECGreduced-36,374-$3.12M
HBMreduced-169,013-$2.56M
CENXreduced-44,107-$1.29M
ENTGreduced-2,996-$277K
AAreduced-8,139-$268K

Ranked by the share change valued at this quarter's implied price (value over shares in the 13F). A position sold out is valued at the previous quarter's price, its last report.

Holdings, Q3 2025

Share positions as resolved from 13F-HR 0000919574-25-006893, largest first. % of portfolio is the value over $171,947,303, the sum of the share positions whose value is usable for ratios (method).

SecurityHistorySharesValue% of portfolioChangeLatest eventTimeline
CENXCENTURY ALUM COQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,407,831 shares; 2024Q4: 647,845 shares; 2025Q1: 639,373 shares; 2025Q2: 705,150 shares; 2025Q3: 661,043 shares 661,043$19.4M11.29%-44,107Timeline
ECGEVERUS CONSTR GROUPQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: 162,722 shares; 2025Q1: 226,857 shares; 2025Q2: 206,218 shares; 2025Q3: 169,844 shares 169,844$14.6M8.47%-36,374Timeline
HBMHUDBAY MINERALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,123,352 shares; 2024Q4: 1,104,563 shares; 2025Q1: 1,161,055 shares; 2025Q2: 1,124,432 shares; 2025Q3: 955,419 shares 955,419$14.5M8.42%-169,013Timeline
CSTMCONSTELLIUM SEQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 549,134 shares; 2024Q4: 887,239 shares; 2025Q1: 542,068 shares; 2025Q2: 845,682 shares; 2025Q3: 833,776 shares 833,776$12.4M7.22%-11,906Timeline
ATIATI INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 140,650 shares; 2024Q4: 182,670 shares; 2025Q1: 181,375 shares; 2025Q2: 122,970 shares; 2025Q3: 144,020 shares 144,020$11.7M6.81%+21,050Timeline
FCXFREEPORT MCMORAN INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 239,045 shares; 2024Q4: 246,840 shares; 2025Q1: 250,558 shares; 2025Q2: 252,961 shares; 2025Q3: 294,049 shares 294,049$11.5M6.71%+41,088Timeline
ENTGENTEGRIS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 98,148 shares; 2024Q4: 99,860 shares; 2025Q1: 98,529 shares; 2025Q2: 126,230 shares; 2025Q3: 123,234 shares 123,234$11.4M6.63%-2,996Timeline
VSHVISHAY INTERTECHNOLOGY INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,102,278 shares; 2024Q4: 516,570 shares; 2025Q1: 659,478 shares; 2025Q2: 742,505 shares; 2025Q3: 742,177 shares 742,177$11.4M6.6%-328Timeline
CRSCARPENTER TECHNOLOGY CORPQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 39,982 shares; 2025Q3: 40,849 shares 40,849$10M5.83%+867Timeline
AAALCOA CORPQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 279,831 shares; 2024Q4: 257,778 shares; 2025Q1: 265,965 shares; 2025Q2: 304,781 shares; 2025Q3: 296,642 shares 296,642$9.76M5.67%-8,139Timeline
SAROSTANDARDAERO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 290,730 shares; 2025Q3: 290,730 shares 290,730$7.93M4.61%0Timeline
BLDRBUILDERS FIRSTSOURCE INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 55,875 shares; 2024Q4: 55,875 shares; 2025Q1: 58,211 shares; 2025Q2: 62,464 shares; 2025Q3: 60,759 shares 60,759$7.37M4.28%-1,705Timeline
AMBPARDAGH METAL PACKAGING S AQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: 1,057,720 shares; 2025Q1: 1,057,720 shares; 2025Q2: 1,538,484 shares; 2025Q3: 1,538,484 shares 1,538,484$6.14M3.57%0Timeline
KEXKIRBY CORPQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 65,431 shares; 2025Q3: 65,431 shares 65,431$5.46M3.18%0Timeline
NXENEXGEN ENERGY LTDQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 564,507 shares; 2024Q4: 564,507 shares; 2025Q1: 564,507 shares; 2025Q2: 564,507 shares; 2025Q3: 564,507 shares 564,507$5.05M2.94%0Timeline
DHID R HORTON INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 50,921 shares; 2024Q4: 51,015 shares; 2025Q1: 53,655 shares; 2025Q2: not reported; 2025Q3: 27,876 shares 27,876$4.72M2.75%newTimeline
SJTSAN JUAN BASIN RTY TRQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 719,054 shares; 2024Q4: 719,054 shares; 2025Q1: 719,054 shares; 2025Q2: 719,054 shares; 2025Q3: 719,054 shares 719,054$4.34M2.53%0Timeline
UECURANIUM ENERGY CORPQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: 320,952 shares 320,952$4.28M2.49%newTimeline

How Q3 2025 was built

Available 13F filings of this filer for the quarter and their roles: the base report is the latest original or restatement, NEW HOLDINGS amendments filed after it are added (method).

FilingRoleAmendmentFiledAcceptedIngested
13F-HR 0000919574-25-006893 base2025-11-14acceptance time not in the bulk data set