Fairmount Funds Management LLC

In its 13F for Q3 2025 (holdings as of September 30, 2025, filed November 14, 2025), Fairmount Funds Management LLC reported 17 stock positions worth $1.1 billion. Its top holding was Dianthus Therapeutics (DNTH) at 11.7% of the portfolio, followed by Cogent Biosciences (COGT, 11.6%) and Axsome Therapeutics (AXSM, 8.9%). Compared with Q2 2025, it opened 1 new position, sold out of 1 and added to 3. The biggest buy was Cogent Biosciences (COGT, shares +45%) and the biggest sale an exit from Cytomx Therapeutics (CTMX).

Most Recent 13F
Q2 2026
Location
WEST CONSHOHOCKEN, PA
CIK
0001802528
Portfolio Value
$1.1B (Q3 2025)
SEC Filing
0001104659-25-112427 ↗ filed Nov 14, 2025

Holdings Value

0$500.0M$1.0B$1.5B$2.0B Q1 2024: $917.4M Q1 2024 Q2 2024: $885.1M Q2 2024 Q3 2024: $1.2B Q3 2024 Q4 2024: $1.0B Q4 2024 Q1 2025: $644.6M Q1 2025 Q2 2025: $771.9M Q2 2025 Q3 2025: $1.1B $1.1B Q3 2025 Q4 2025: $1.3B Q4 2025 Q1 2026: $1.4B Q1 2026 Q2 2026: $1.5B Q2 2026

Holdings 17 stocks · $1.1B
DNTH Dianthus Therapeutics Inc. 11.71% 3,307,191 $130.1M Add +22.2%
COGT Cogent Biosciences Inc. 11.63% 9,003,418 $129.3M Add +44.6%
AXSM Axsome Therapeutics Inc. 8.91% 815,176 $99.0M No change
APGE Apogee Therapeutics Inc. 7.32% 2,048,647 $81.4M No change
ELVN Enliven Therapeutics Inc. 6.84% 3,711,444 $76.0M No change
VRDN Viridian Therapeutics Inc. 6.72% 3,459,913 $74.7M No change
ORKA Oruka Therapeutics Inc. 6.41% 3,705,262 $71.3M Add +9.9%
KNSA Kiniksa Pharmaceuticals Inte 6.19% 1,772,839 $68.8M No change
SRRK Scholar Rock Holding Corp. 6.11% 1,824,031 $67.9M No change
SYRE Spyre Therapeutics Inc. 6.06% 4,018,101 $67.3M No change
NUVL Nuvalent Inc. Class A 5.66% 727,563 $62.9M No change
ABVX Abivax SA-ADR 5.45% 713,434 $60.6M New
ZBIO Zenas Biopharma Inc. 3.78% 1,892,806 $42.0M No change
JBIO Jade Biosciences Inc. 2.50% 3,220,368 $27.8M No change
ATXS Astria Therapeutics Inc. 2.33% 3,554,129 $25.9M No change
CBIO Crescent Biopharma Inc. 1.48% 1,387,866 $16.5M No change
IKT Inhibikase Therapeutics Inc. 0.89% 6,125,000 $9.9M No change

Portfolio Sells Q2 2025 → Q3 2025
CTMX Cytomx Therapeutics Inc. Sold out 0.00% −1.15

Portfolio Buys Q2 2025 → Q3 2025
COGT Cogent Biosciences Inc. Add +44.6% 11.63% +5.84
ABVX Abivax SA-ADR New 5.45% +5.45
DNTH Dianthus Therapeutics Inc. Add +22.2% 11.71% +5.18
ORKA Oruka Therapeutics Inc. Add +9.9% 6.41% +1.51

All Filings

QuarterPositions13F Reported ValueTop Holdings
Q2 2026 12$1.5BORKA, DNTH, DMRA, COGT, JBIO
Q1 2026 12$1.4BDMRA, DNTH, COGT, SYRE, ORKA
Q4 2025 13$1.3BCOGT, APGE, SYRE, VRDN, ORKA
Q3 2025 17$1.1BDNTH, COGT, AXSM, APGE, ELVN
Q2 2025 17$771.9MAPGE, AXSM, ELVN, SRRK, SYRE
Q1 2025 15$644.6MAXSM, APGE, SYRE, ELVN, NUVL
Q4 2024 17$1.0BAXSM, NUVL, SYRE, APGE, SRRK
Q3 2024 15$1.2BAXSM, NUVL, APGE, SYRE, ELVN
Q2 2024 13$885.1MAXSM, NUVL, SYRE, APGE, ELVN
Q1 2024 15$917.4MAXSM, NUVL, APGE, DNTH, KNSA