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Fairmount Funds Management LLC

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13F filer, CIK 1802528, WEST CONSHOHOCKEN, PA

Fairmount Funds Management LLC reported $1,111,423,463 across 17 holdings for the quarter ended 2025-09-30, in a 13F-HR filed 2025-11-14. Its ten largest share positions make up 77.9% of the portfolio.

Filed (acceptance time not in the bulk data set), ingested 13F-HR 0001104659-25-112427

Period
2025-09-30
Reported value
$1.11B
Holdings
17
Top 10 weight
77.9%
New
1
Sold out
1

Part of the filer group Fairmount Funds Management LLC

  • Fairmount Healthcare Fund II L.P.
  • Harwin Peter Evan
  • Kiselak Tomas
How groups are built

Largest buys vs the previous quarter

SecurityShares changeApprox. value
ABVXnew+713,434$60.6M
COGTadded+2,777,777$39.9M
DNTHadded+600,000$23.6M
ORKAadded+333,340$6.41M

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
CTMXexited-3,896,582-$8.85M

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 0001104659-25-112427, largest first. % of portfolio is the value over $1,111,423,463, the sum of the share positions whose value is usable for ratios (method).

SecurityHistorySharesValue% of portfolioChangeLatest eventTimeline
DNTHDIANTHUS THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 2,700,691 shares; 2024Q4: 2,700,691 shares; 2025Q1: 2,700,691 shares; 2025Q2: 2,707,191 shares; 2025Q3: 3,307,191 shares 3,307,191$130M11.71%+600,000Timeline
COGTCOGENT BIOSCIENCES INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 6,225,641 shares; 2024Q4: 6,225,641 shares; 2025Q1: 6,225,641 shares; 2025Q2: 6,225,641 shares; 2025Q3: 9,003,418 shares 9,003,418$129M11.63%+2,777,777Timeline
AXSMAXSOME THERAPEUTICS INC.Quarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 2,360,077 shares; 2024Q4: 1,468,983 shares; 2025Q1: 815,176 shares; 2025Q2: 815,176 shares; 2025Q3: 815,176 shares 815,176$99M8.91%0Timeline
APGEAPOGEE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 2,048,647 shares; 2024Q4: 2,048,647 shares; 2025Q1: 2,048,647 shares; 2025Q2: 2,048,647 shares; 2025Q3: 2,048,647 shares 2,048,647$81.4M7.32%0Timeline
ELVNENLIVEN THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 3,202,798 shares; 2024Q4: 3,202,798 shares; 2025Q1: 3,202,798 shares; 2025Q2: 3,711,444 shares; 2025Q3: 3,711,444 shares 3,711,444$76M6.84%0Timeline
VRDNVIRIDIAN THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 3,445,813 shares; 2024Q4: 3,445,813 shares; 2025Q1: 3,445,813 shares; 2025Q2: 3,459,913 shares; 2025Q3: 3,459,913 shares 3,459,913$74.7M6.72%0Timeline
ORKAORUKA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 3,211,922 shares; 2024Q4: 3,371,922 shares; 2025Q1: 3,371,922 shares; 2025Q2: 3,371,922 shares; 2025Q3: 3,705,262 shares 3,705,262$71.3M6.41%+333,340Timeline
KNSAKINIKSA PHARMACEUTICALS INTLQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 3,204,841 shares; 2024Q4: 2,194,341 shares; 2025Q1: 1,102,248 shares; 2025Q2: 1,772,839 shares; 2025Q3: 1,772,839 shares 1,772,839$68.8M6.19%0Timeline
SRRKSCHOLAR ROCK HLDG CORPQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: 1,962,953 shares; 2025Q1: 1,374,031 shares; 2025Q2: 1,824,031 shares; 2025Q3: 1,824,031 shares 1,824,031$67.9M6.11%0Timeline
SYRESPYRE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 4,018,101 shares; 2024Q4: 4,018,101 shares; 2025Q1: 4,018,101 shares; 2025Q2: 4,018,101 shares; 2025Q3: 4,018,101 shares 4,018,101$67.3M6.06%02026-10-07, 13D/A: 10,185,961 shares, 9.99% of the class, 13D/A filed 2026-10-09 Timeline
NUVLNUVALENT INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,687,064 shares; 2024Q4: 1,317,664 shares; 2025Q1: 727,563 shares; 2025Q2: 727,563 shares; 2025Q3: 727,563 shares 727,563$62.9M5.66%0Timeline
ABVXABIVAX SAQuarterly 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: 713,434 shares 713,434$60.6M5.45%newTimeline
ZBIOZENAS BIOPHARMA INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,892,806 shares; 2024Q4: 1,892,806 shares; 2025Q1: 1,892,806 shares; 2025Q2: 1,892,806 shares; 2025Q3: 1,892,806 shares 1,892,806$42M3.78%0Timeline
JBIOJADE BIOSCIENCES 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: 3,220,368 shares; 2025Q3: 3,220,368 shares 3,220,368$27.8M2.5%0Timeline
ASTRIA THERAPEUTICS INCASTRIA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 3,554,129 shares; 2024Q4: 3,554,129 shares; 2025Q1: 3,554,129 shares; 2025Q2: 3,554,129 shares; 2025Q3: 3,554,129 shares 3,554,129$25.9M2.33%0
CBIOCRESCENT BIOPHARMA INC.Quarterly 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: 1,387,866 shares; 2025Q3: 1,387,866 shares 1,387,866$16.5M1.48%0Timeline
IKTINHIBIKASE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: 6,125,000 shares; 2025Q1: 6,125,000 shares; 2025Q2: 6,125,000 shares; 2025Q3: 6,125,000 shares 6,125,000$9.92M0.89%0Timeline

Sold out in Q3 2025

Positions in the previous quarter's report that this quarter's report no longer lists.

SecurityShares beforeValue beforeType
CTMXCYTOMX THERAPEUTICS INC.3,896,582$8.85Mshares

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 0001104659-25-112427 base2025-11-14acceptance time not in the bulk data set