Rock Springs Capital Management LP
In its 13F for Q3 2025 (holdings as of September 30, 2025, filed November 14, 2025), Rock Springs Capital Management LP reported 90 stock positions worth $1.7 billion. Its top holding was Argenx SE - ADR (ARGX) at 6.2% of the portfolio, followed by Eli Lilly (LLY, 4.7%) and Rhythm Pharmaceuticals (RYTM, 4.3%). Compared with Q2 2025, it opened 8 new positions, sold out of 9, added to 24 and reduced 35. The biggest buy was Travere Therapeutics (TVTX, shares +13%) and the biggest sale an exit from Blueprint Medicines (BPMC).
- Most Recent 13F
- Q2 2026
- Location
- Baltimore, MD
- CIK
- 0001595725
- Portfolio Value
- $1.7B (Q3 2025)
- SEC Filing
- 0001172661-25-004882 ↗ filed Nov 14, 2025
Holdings Value
Holdings 90 stocks · $1.7B
| ARGX Argenx SE - ADR | 6.18% | 142,750 | $105.3M | Reduce -18.8% |
| LLY Eli Lilly & Co. | 4.72% | 105,400 | $80.4M | Reduce -9.5% |
| RYTM Rhythm Pharmaceuticals Inc. | 4.25% | 717,102 | $72.4M | Reduce -16.7% |
| MDGL Madrigal Pharmaceuticals Inc. | 3.71% | 137,746 | $63.2M | Reduce -1.8% |
| RVMD Revolution Medicines Inc. | 3.66% | 1,335,270 | $62.4M | Add +0.3% |
| MRUS Merus NV | 3.30% | 597,051 | $56.2M | Reduce -43.9% |
| MIRM Mirum Pharmaceuticals Inc. | 3.27% | 761,126 | $55.8M | Reduce -7.0% |
| INSM Insmed Inc. | 3.25% | 385,000 | $55.4M | Reduce -26.7% |
| TVTX Travere Therapeutics Inc. | 3.04% | 2,164,773 | $51.7M | Add +13.4% |
| ASND Ascendis Pharma A/S | 2.50% | 214,500 | $42.6M | Reduce -1.1% |
| IRTC Irhythm Holdings Inc. | 2.37% | 235,000 | $40.4M | Reduce -3.1% |
| AGIO Agios Pharmaceuticals Inc. | 2.26% | 958,542 | $38.5M | Reduce -3.1% |
| RARE Ultragenyx Pharmaceutical Inc. | 2.20% | 1,246,341 | $37.5M | Reduce -10.4% |
| ISRG Intuitive Surgical Inc. | 2.15% | 82,000 | $36.7M | No change |
| BSX Boston Scientific Corp. | 2.06% | 360,250 | $35.2M | Add +1.5% |
| XENE Xenon Pharmaceuticals Inc. | 2.01% | 851,744 | $34.2M | Reduce -8.6% |
| ALNY Alnylam Pharmaceuticals Inc. | 1.99% | 74,250 | $33.9M | Reduce -25.8% |
| EXAS Exact Sciences Corp. | 1.91% | 593,500 | $32.5M | Add +3.8% |
| PEN Penumbra Inc. | 1.79% | 120,500 | $30.5M | Reduce -6.2% |
| AKRO Akero Therapeutics Inc. | 1.75% | 626,526 | $29.7M | Reduce -2.2% |
| SRRK Scholar Rock Holding Corp. | 1.74% | 794,133 | $29.6M | No change |
| ZLAB Zai Lab Ltd.-ADR | 1.57% | 791,193 | $26.8M | Reduce -9.2% |
| GPCR Structure Therapeutics Inc. | 1.56% | 951,154 | $26.6M | Reduce -16.3% |
| KYMR Kymera Therapeutics Inc. | 1.50% | 450,374 | $25.5M | No change |
| THC Tenet Healthcare Corp. | 1.49% | 125,000 | $25.4M | Reduce -3.9% |
| EVH Evolent Health Inc. Class A | 1.46% | 2,950,000 | $25.0M | Add +4.6% |
| CAI Caris Life Sciences Inc. | 1.41% | 793,651 | $24.0M | No change |
| CDTX Cidara Therapeutics Inc. | 1.40% | 249,402 | $23.9M | Add +85.9% |
| DXCM Dexcom Inc. | 1.25% | 316,900 | $21.3M | Add +10.5% |
| OMDA Omada Health Inc. | 1.19% | 919,950 | $20.3M | Reduce 0.0% |
| CLDX Celldex Therapeutics Inc. | 1.10% | 721,538 | $18.7M | Reduce -11.2% |
| VERA Vera Therapeutics Inc. | 1.05% | 617,396 | $17.9M | No change |
| PHR Phreesia Inc. | 1.03% | 749,116 | $17.6M | Reduce -10.5% |
| TARS Tarsus Pharmaceuticals Inc. | 1.01% | 288,344 | $17.1M | Reduce -22.9% |
| NAMS Newamsterdam Pharma Co. NV | 0.99% | 595,929 | $16.9M | Add +11.2% |
| CMPX Compass Therapeutics Inc. | 0.92% | 4,474,702 | $15.7M | Reduce -9.8% |
| PHVS Pharvaris NV | 0.91% | 623,402 | $15.6M | No change |
| AZTA Azenta Inc. | 0.91% | 540,400 | $15.5M | Add +1.9% |
| MLYS Mineralys Therapeutics Inc. | 0.91% | 408,313 | $15.5M | Add +25.8% |
| FOLD Amicus Therapeutics Inc. | 0.90% | 1,947,374 | $15.3M | Reduce -0.7% |
| XBI SS SPDR S&P Biotech ETF | 0.89% | 151,750 | $15.2M | No change |
| ACLX Arcellx Inc. | 0.86% | 178,982 | $14.7M | Reduce -3.9% |
| SMMT Summit Therapeutics Inc. | 0.86% | 710,000 | $14.7M | No change |
| COGT Cogent Biosciences Inc. | 0.85% | 1,008,308 | $14.5M | Add +26.0% |
| ELVN Enliven Therapeutics Inc. | 0.82% | 686,107 | $14.0M | Reduce -2.2% |
| ZBIO Zenas Biopharma Inc. | 0.76% | 580,677 | $12.9M | Reduce -9.3% |
| NBIX Neurocrine Biosciences Inc. | 0.74% | 89,750 | $12.6M | Add +1.1% |
| ARDX Ardelyx Inc. | 0.74% | 2,286,273 | $12.6M | No change |
| DHR Danaher Corp. | 0.72% | 61,500 | $12.2M | Add +4.2% |
| LENZ Lenz Therapeutics Inc. | 0.65% | 236,227 | $11.0M | Add +181.3% |
| SLNO Soleno Therapeutics Inc. | 0.61% | 154,528 | $10.4M | No change |
| DYN Dyne Therapeutics Inc. | 0.61% | 824,061 | $10.4M | Add +41.8% |
| MREO Mereo Biopharma Group PL-ADR | 0.55% | 4,570,649 | $9.4M | Add +2.4% |
| ACRS Aclaris Therapeutics Inc. | 0.51% | 4,609,309 | $8.8M | Reduce -3.4% |
| GOSS Gossamer Bio Inc. | 0.50% | 3,266,960 | $8.6M | No change |
| HTFL Heartflow Inc. | 0.49% | 250,000 | $8.4M | New |
| INSP Inspire Medical Systems Inc. | 0.48% | 110,500 | $8.2M | Add +2.8% |
| AGL Agilon Health Inc. | 0.42% | 6,966,300 | $7.2M | Add +6.3% |
| EW Edwards Lifesciences Corp. | 0.40% | 88,000 | $6.8M | Reduce -32.8% |
| AMLX Amylyx Pharmaceuticals Inc. | 0.40% | 499,764 | $6.8M | No change |
| REGN Regeneron Pharmaceuticals | 0.37% | 11,300 | $6.4M | No change |
| BCAX Bicara Therapeutics Inc. | 0.34% | 370,666 | $5.9M | Add +10.3% |
| JANX Janux Therapeutics Inc. | 0.30% | 210,366 | $5.1M | Add +0.1% |
| MBX MBX Biosciences Inc. | 0.29% | 282,624 | $4.9M | New |
| TMO Thermo Fisher Scientific Inc. | 0.28% | 10,000 | $4.9M | No change |
| BBIO Bridgebio Pharma Inc. | 0.26% | 85,000 | $4.4M | New |
| ATEC Alphatec Holdings Inc. | 0.26% | 302,500 | $4.4M | Add +13.1% |
| ACHC Acadia Healthcare Co. Inc. | 0.25% | 170,000 | $4.2M | Reduce -75.6% |
| OCUL Ocular Therapeutix Inc. | 0.21% | 300,000 | $3.5M | New |
| TLPH Talphera Inc. | 0.19% | 3,589,186 | $3.2M | Add +1034.2% |
| ALKS Alkermes PLC | 0.19% | 106,537 | $3.2M | New |
| SION Sionna Therapeutics Inc. | 0.17% | 99,429 | $2.9M | No change |
| FOCL Edap TMS SA -ADR | 0.17% | 1,270,000 | $2.9M | No change |
| JSPR Jasper Therapeutics Inc. | 0.15% | 1,100,726 | $2.6M | Add +101.9% |
| WST West Pharmaceutical Services | 0.15% | 9,750 | $2.6M | Reduce -80.9% |
| APLS Apellis Pharmaceuticals Inc. | 0.12% | 92,000 | $2.1M | Add +9.1% |
| NGNE Neurogene Inc. | 0.11% | 104,339 | $1.8M | No change |
| KRRO Korro Bio Inc. | 0.10% | 35,719 | $1.7M | No change |
| CNTA Centessa Pharmaceuticals Ltd. | 0.10% | 69,240 | $1.7M | New |
| CATX Perspective Therapeutics Inc. | 0.09% | 444,383 | $1.5M | No change |
| APLT Applied Therapeutics Inc. | 0.07% | 2,075,991 | $1.3M | No change |
| MRSN Mersana Therapeutics Inc. | 0.07% | 152,586 | $1.2M | No change |
| IMVT Immunovant Inc. | 0.07% | 72,965 | $1.2M | Reduce -67.1% |
| EYPT Eyepoint Inc. | 0.03% | 31,655 | $451K | New |
| CRL Charles River Laboratories | 0.02% | 2,700 | $422K | No change |
| PCVX Vaxcyte Inc. | 0.02% | 11,100 | $400K | No change |
| NVAX Novavax Inc. | 0.02% | 45,000 | $390K | Reduce -16.5% |
| PRTA Prothena Corp. PLC | 0.01% | 25,398 | $248K | Reduce -94.8% |
| MLTX Moonlake Immunotherapeutics | 0.01% | 28,200 | $202K | New |
| CGEN Compugen Ltd. | 0.00% | 13,430 | $20K | Reduce -98.6% |
Options reported separately and not counted above: NAMS calls ($899K).
Other holdings (2): bonds, preferreds, convertibles and warrants · $6.7M (not counted above)
| Security | Class | Shares / Principal | Value | Change |
|---|---|---|---|---|
| GOSSAMER BIO INC (GOSS 5 06/01/27) | NOTE 5.000% 6/0 · principal | 9,573,000 | $6.7M | No change |
| NUVB.WS Nuvation Bio Inc. -CW27 | *W EXP 02/10/202 | 134,028 | $27K | No change |
Total filed on the 13F, all lines: $1.7B.
Portfolio Sells Q2 2025 → Q3 2025
| BPMC Blueprint Medicines Corp. | Sold out | 0.00% | −1.49 |
| UNH Unitedhealth Group Inc. | Sold out | 0.00% | −0.98 |
| RARE Ultragenyx Pharmaceutical Inc. | Reduce -10.4% | 2.20% | −0.96 |
| LLY Eli Lilly & Co. | Reduce -9.5% | 4.72% | −0.96 |
| OSCR Oscar Health Inc. Class A | Sold out | 0.00% | −0.94 |
| ACHC Acadia Healthcare Co. Inc. | Reduce -75.6% | 0.25% | −0.74 |
| WST West Pharmaceutical Services | Reduce -80.9% | 0.15% | −0.55 |
| PHR Phreesia Inc. | Reduce -10.5% | 1.03% | −0.46 |
| NUVL Nuvalent Inc. Class A | Sold out | 0.00% | −0.45 |
| AKRO Akero Therapeutics Inc. | Reduce -2.2% | 1.75% | −0.39 |
| ZLAB Zai Lab Ltd.-ADR | Reduce -9.2% | 1.57% | −0.33 |
| CGEM Cullinan Therapeutics Inc. | Sold out | 0.00% | −0.31 |
| PEN Penumbra Inc. | Reduce -6.2% | 1.79% | −0.27 |
| EW Edwards Lifesciences Corp. | Reduce -32.8% | 0.40% | −0.24 |
| MRUS Merus NV | Reduce -43.9% | 3.30% | −0.20 |
| PRTA Prothena Corp. PLC | Reduce -94.8% | 0.01% | −0.17 |
| IMVT Immunovant Inc. | Reduce -67.1% | 0.07% | −0.15 |
| CGEN Compugen Ltd. | Reduce -98.6% | 0.00% | −0.11 |
| LUNG Pulmonx Corp. | Sold out | 0.00% | −0.11 |
| SRPT Sarepta Therapeutics Inc. | Sold out | 0.00% | −0.07 |
| ELVN Enliven Therapeutics Inc. | Reduce -2.2% | 0.82% | −0.06 |
| ALNY Alnylam Pharmaceuticals Inc. | Reduce -25.8% | 1.99% | −0.05 |
| INSM Insmed Inc. | Reduce -26.7% | 3.25% | −0.05 |
| ADAPY Adaptimmune Therapeutics-ADR | Sold out | 0.00% | −0.04 |
| ETNB 89BIO Inc. | Sold out | 0.00% | −0.02 |
| NVAX Novavax Inc. | Reduce -16.5% | 0.02% | +0.00 |
| IRTC Irhythm Holdings Inc. | Reduce -3.1% | 2.37% | +0.04 |
| TARS Tarsus Pharmaceuticals Inc. | Reduce -22.9% | 1.01% | +0.06 |
| THC Tenet Healthcare Corp. | Reduce -3.9% | 1.49% | +0.06 |
| CLDX Celldex Therapeutics Inc. | Reduce -11.2% | 1.10% | +0.06 |
| GPCR Structure Therapeutics Inc. | Reduce -16.3% | 1.56% | +0.09 |
| ACRS Aclaris Therapeutics Inc. | Reduce -3.4% | 0.51% | +0.09 |
| ACLX Arcellx Inc. | Reduce -3.9% | 0.86% | +0.10 |
| CMPX Compass Therapeutics Inc. | Reduce -9.8% | 0.92% | +0.11 |
| ARGX Argenx SE - ADR | Reduce -18.8% | 6.18% | +0.12 |
| OMDA Omada Health Inc. | Reduce 0.0% | 1.19% | +0.14 |
| ASND Ascendis Pharma A/S | Reduce -1.1% | 2.50% | +0.16 |
| XENE Xenon Pharmaceuticals Inc. | Reduce -8.6% | 2.01% | +0.18 |
| FOLD Amicus Therapeutics Inc. | Reduce -0.7% | 0.90% | +0.20 |
| AGIO Agios Pharmaceuticals Inc. | Reduce -3.1% | 2.26% | +0.20 |
| ZBIO Zenas Biopharma Inc. | Reduce -9.3% | 0.76% | +0.37 |
| MIRM Mirum Pharmaceuticals Inc. | Reduce -7.0% | 3.27% | +0.67 |
| RYTM Rhythm Pharmaceuticals Inc. | Reduce -16.7% | 4.25% | +0.85 |
| MDGL Madrigal Pharmaceuticals Inc. | Reduce -1.8% | 3.71% | +1.05 |
Portfolio Buys Q2 2025 → Q3 2025
| TVTX Travere Therapeutics Inc. | Add +13.4% | 3.04% | +1.27 |
| CDTX Cidara Therapeutics Inc. | Add +85.9% | 1.40% | +0.99 |
| MLYS Mineralys Therapeutics Inc. | Add +25.8% | 0.91% | +0.63 |
| RVMD Revolution Medicines Inc. | Add +0.3% | 3.66% | +0.60 |
| HTFL Heartflow Inc. | New | 0.49% | +0.49 |
| LENZ Lenz Therapeutics Inc. | Add +181.3% | 0.65% | +0.49 |
| COGT Cogent Biosciences Inc. | Add +26.0% | 0.85% | +0.49 |
| NAMS Newamsterdam Pharma Co. NV | Add +11.2% | 0.99% | +0.39 |
| MBX MBX Biosciences Inc. | New | 0.29% | +0.29 |
| DYN Dyne Therapeutics Inc. | Add +41.8% | 0.61% | +0.27 |
| BBIO Bridgebio Pharma Inc. | New | 0.26% | +0.26 |
| OCUL Ocular Therapeutix Inc. | New | 0.21% | +0.21 |
| ALKS Alkermes PLC | New | 0.19% | +0.19 |
| TLPH Talphera Inc. | Add +1034.2% | 0.19% | +0.18 |
| BCAX Bicara Therapeutics Inc. | Add +10.3% | 0.34% | +0.15 |
| CNTA Centessa Pharmaceuticals Ltd. | New | 0.10% | +0.10 |
| ATEC Alphatec Holdings Inc. | Add +13.1% | 0.26% | +0.07 |
| NBIX Neurocrine Biosciences Inc. | Add +1.1% | 0.74% | +0.04 |
| APLS Apellis Pharmaceuticals Inc. | Add +9.1% | 0.12% | +0.03 |
| EYPT Eyepoint Inc. | New | 0.03% | +0.03 |
| MLTX Moonlake Immunotherapeutics | New | 0.01% | +0.01 |
| EXAS Exact Sciences Corp. | Add +3.8% | 1.91% | +0.01 |
| JANX Janux Therapeutics Inc. | Add +0.1% | 0.30% | −0.00 |
| DHR Danaher Corp. | Add +4.2% | 0.72% | −0.01 |
| JSPR Jasper Therapeutics Inc. | Add +101.9% | 0.15% | −0.04 |
| AZTA Azenta Inc. | Add +1.9% | 0.91% | −0.11 |
| MREO Mereo Biopharma Group PL-ADR | Add +2.4% | 0.55% | −0.20 |
| DXCM Dexcom Inc. | Add +10.5% | 1.25% | −0.31 |
| BSX Boston Scientific Corp. | Add +1.5% | 2.06% | −0.32 |
| INSP Inspire Medical Systems Inc. | Add +2.8% | 0.48% | −0.39 |
| AGL Agilon Health Inc. | Add +6.3% | 0.42% | −0.52 |
| EVH Evolent Health Inc. Class A | Add +4.6% | 1.46% | −0.52 |
Options Activity Q2 2025 → Q3 2025
| NAMS Newamsterdam Pharma Co. NV | call | New | 31,600 | $899K |
Calls and puts are listed by the shares they cover; their value is not part of the stock holdings above.
All Filings
| Quarter | Positions | 13F Reported Value | Top Holdings |
|---|---|---|---|
| Q2 2026 | 104 | $2.0B | RVMD, TVTX, LLY, MDGL, MIRM |
| Q1 2026 | 100 | $1.7B | RVMD, LLY, MDGL, MIRM, ARGX |
| Q4 2025 | 96 | $1.9B | LLY, RVMD, ARGX, TVTX, MDGL |
| Q3 2025 | 90 | $1.7B | ARGX, LLY, RYTM, MDGL, RVMD |
| Q2 2025 | 91 | $1.6B | ARGX, LLY, MRUS, RYTM, INSM |
| Q1 2025 | 94 | $1.7B | ARGX, LLY, BPMC, MDGL, UNH |
| Q4 2024 | 104 | $2.6B | ARGX, ISRG, LLY, NBIX, BPMC |
| Q3 2024 | 106 | $3.1B | UNH, ISRG, ARGX, LLY, RARE |
| Q2 2024 | 106 | $3.3B | BPMC, UNH, ISRG, NBIX, LLY |
| Q1 2024 | 108 | $3.9B | BPMC, IMCR, NBIX, EVH, ISRG |