Rock Springs Capital Management LP

In its 13F for Q1 2024 (holdings as of March 31, 2024, filed May 15, 2024), Rock Springs Capital Management LP reported 108 stock positions worth $3.9 billion. Its top holding was Blueprint Medicines (BPMC) at 6.0% of the portfolio, followed by Immunocore Holdings PLC-ADR (IMCR, 3.9%) and Neurocrine Biosciences (NBIX, 3.7%). Compared with Q4 2023, it opened 16 new positions, sold out of 6, added to 40 and reduced 11. The biggest buy was Eli Lilly (LLY, shares +49%) and the biggest sale an exit from Karuna Therapeutics (KRTX).

Most Recent 13F
Q2 2026
Location
Baltimore, MD
CIK
0001595725
Portfolio Value
$3.9B (Q1 2024)
SEC Filing
0001172661-24-002385 ↗ filed May 15, 2024

Holdings Value

0$1.0B$2.0B$3.0B$4.0B Q1 2024: $3.9B $3.9B Q1 2024 Q2 2024: $3.3B Q2 2024 Q3 2024: $3.1B Q3 2024 Q4 2024: $2.6B Q4 2024 Q1 2025: $1.7B Q1 2025 Q2 2025: $1.6B Q2 2025 Q3 2025: $1.7B Q3 2025 Q4 2025: $1.9B Q4 2025 Q1 2026: $1.7B Q1 2026 Q2 2026: $2.0B Q2 2026

Holdings 108 stocks · $3.9B
BPMC Blueprint Medicines Corp. 6.04% 2,498,448 $237.0M Reduce -13.3%
IMCR Immunocore Holdings PLC-ADR 3.92% 2,367,816 $153.9M Reduce -11.0%
NBIX Neurocrine Biosciences Inc. 3.71% 1,054,900 $145.5M Reduce -11.8%
EVH Evolent Health Inc. Class A 3.33% 3,987,500 $130.8M Add +0.7%
ISRG Intuitive Surgical Inc. 3.04% 298,500 $119.1M No change
UNH Unitedhealth Group Inc. 2.90% 230,000 $113.8M No change
PEN Penumbra Inc. 2.87% 505,000 $112.7M Reduce -6.0%
IDXX Idexx Laboratories Inc. 2.47% 179,250 $96.8M No change
ACHC Acadia Healthcare Co. Inc. 2.38% 1,177,500 $93.3M Add +9.7%
ARGX Argenx SE - ADR 2.30% 229,250 $90.3M No change
BSX Boston Scientific Corp. 2.15% 1,232,500 $84.4M No change
RARE Ultragenyx Pharmaceutical Inc. 2.11% 1,774,938 $82.9M Add +1.2%
DXCM Dexcom Inc. 2.11% 596,750 $82.8M Add +0.1%
LLY Eli Lilly & Co. 2.05% 103,250 $80.3M Add +48.6%
FRPT Freshpet Inc. 1.96% 662,500 $76.8M No change
MDGL Madrigal Pharmaceuticals Inc. 1.95% 285,931 $76.4M Add +44.3%
EXAS Exact Sciences Corp. 1.86% 1,059,750 $73.2M Add +4.0%
ALGN Align Technology Inc. 1.84% 220,000 $72.1M No change
RYTM Rhythm Pharmaceuticals Inc. 1.68% 1,522,893 $66.0M No change
EW Edwards Lifesciences Corp. 1.58% 647,300 $61.9M No change
KYMR Kymera Therapeutics Inc. 1.56% 1,522,238 $61.2M No change
CLDX Celldex Therapeutics Inc. 1.47% 1,372,185 $57.6M Add +41.5%
PHR Phreesia Inc. 1.44% 2,365,000 $56.6M Add +7.2%
PODD Insulet Corp. 1.40% 320,000 $54.8M Reduce -25.9%
WST West Pharmaceutical Services 1.38% 137,250 $54.3M No change
XENE Xenon Pharmaceuticals Inc. 1.38% 1,255,577 $54.1M No change
AGL Agilon Health Inc. 1.37% 8,835,000 $53.9M Add +2.4%
MRUS Merus NV 1.32% 1,146,560 $51.6M Add +31.5%
AGIO Agios Pharmaceuticals Inc. 1.31% 1,764,505 $51.6M Reduce -18.0%
HUM Humana Inc. 1.30% 147,408 $51.1M Reduce -52.5%
MIRM Mirum Pharmaceuticals Inc. 1.19% 1,856,564 $46.6M Add +0.3%
IRTC Irhythm Holdings Inc. 1.16% 392,250 $45.5M Add +11.8%
SWAV Shockwave Medical Inc. 1.12% 135,000 $44.0M Add +12.5%
ASND Ascendis Pharma A/S 1.12% 290,000 $43.8M No change
SRPT Sarepta Therapeutics Inc. 1.08% 327,600 $42.4M No change
AZTA Azenta Inc. 1.07% 694,750 $41.9M Add +36.9%
OLK Olink Holding AB - ADR 1.00% 1,676,500 $39.4M No change
IMVT Immunovant Inc. 0.95% 1,150,123 $37.2M Add +17.0%
ACCD Accolade Inc. 0.95% 3,540,000 $37.1M Add +1.6%
ALNY Alnylam Pharmaceuticals Inc. 0.93% 244,000 $36.5M Add +3.8%
AKRO Akero Therapeutics Inc. 0.84% 1,299,888 $32.8M Add +20.2%
OSCR Oscar Health Inc. Class A 0.80% 2,110,000 $31.4M Add +187.1%
PCRX Pacira Biosciences Inc. 0.79% 1,055,500 $30.8M No change
RVMD Revolution Medicines Inc. 0.76% 923,681 $29.8M Add +27.4%
LFST Lifestance Health Group Inc. 0.75% 4,780,000 $29.5M Add +5.4%
SGRY Surgery Partners Inc. 0.75% 985,000 $29.4M New
WRBY Warby Parker Inc. Class A 0.72% 2,080,000 $28.3M Add +2.5%
INZY Inozyme Pharma Inc. 0.72% 3,681,174 $28.2M No change
INSP Inspire Medical Systems Inc. 0.71% 130,500 $28.0M Add +31.8%
LEGN Legend Biotech Corp.-ADR 0.71% 499,486 $28.0M Add +1.4%
MREO Mereo Biopharma Group PL-ADR 0.68% 8,142,109 $26.9M Add +2.0%
TVTX Travere Therapeutics Inc. 0.67% 3,424,818 $26.4M Add +23.6%
CERE Cerevel Therapeutics Holding 0.59% 547,946 $23.2M Reduce -79.5%
IRON Disc Medicine Inc. 0.58% 363,468 $22.6M No change
COLL Collegium Pharmaceutical Inc. 0.56% 562,000 $21.8M No change
VKTX Viking Therapeutics Inc. 0.55% 261,000 $21.4M New
DVAX Dynavax Technologies Corp. 0.53% 1,675,474 $20.8M No change
ZLAB Zai Lab Ltd.-ADR 0.53% 1,297,123 $20.8M Add +14.1%
MGNX Macrogenics Inc. 0.49% 1,305,250 $19.2M Add +10.7%
NVO Novo-Nordisk A/S-Spons ADR 0.48% 147,500 $18.9M New
KRYS Krystal Biotech Inc. 0.47% 103,969 $18.5M No change
BCRX Biocryst Pharmaceuticals Inc. 0.45% 3,496,256 $17.8M Add +6.9%
GPCR Structure Therapeutics Inc. 0.45% 412,649 $17.7M Add +43.9%
PHVS Pharvaris NV 0.44% 752,924 $17.4M New
PRTA Prothena Corp. PLC 0.39% 625,048 $15.5M No change
NVRO Nevro LLC filed as NEVRO CORP 0.39% 1,065,000 $15.4M Add +3.9%
VERA Vera Therapeutics Inc. 0.37% 341,168 $14.7M New
MERSANA THERAPEUTICS INC 0.35% 3,046,782 $13.6M No change
FOLD Amicus Therapeutics Inc. 0.35% 1,152,656 $13.6M Add +8.3%
CRNX Crinetics Pharmaceuticals Inc. 0.35% 289,400 $13.5M New
CRL Charles River Laboratories 0.33% 48,500 $13.1M New
BMRN Biomarin Pharmaceutical Inc. 0.33% 148,832 $13.0M No change
DYN Dyne Therapeutics Inc. 0.33% 451,824 $12.8M New
JSPR Jasper Therapeutics Inc. 0.30% 404,335 $11.9M New
CMPX Compass Therapeutics Inc. 0.28% 5,513,788 $10.9M No change
FOCL Edap TMS SA -ADR 0.28% 1,475,000 $10.8M Add +6.4%
MLYS Mineralys Therapeutics Inc. 0.26% 792,615 $10.2M Reduce -32.1%
APLT Applied Therapeutics Inc. 0.26% 1,497,918 $10.2M Add +67.3%
NUVL Nuvalent Inc. Class A 0.24% 125,302 $9.4M New
ABOS Acumen Pharmaceuticals Inc. 0.24% 2,300,059 $9.3M No change
IMTX Immatics NV 0.23% 848,751 $8.9M Reduce -54.7%
NMRA Neumora Therapeutics Inc. 0.23% 646,118 $8.9M New
ELVN Enliven Therapeutics Inc. 0.19% 428,571 $7.5M New
CGON CG Oncology Inc. 0.19% 170,859 $7.5M New
BHVN Biohaven Ltd. 0.18% 126,984 $6.9M New
FULC Fulcrum Therapeutics Inc. 0.17% 727,673 $6.9M No change
AUTL Autolus Therapeutics PLC 0.17% 1,032,988 $6.6M New
LUNG Pulmonx Corp. 0.15% 652,400 $6.0M No change
AUPH Aurinia Pharmaceuticals Inc. 0.15% 1,150,347 $5.8M Add +178.8%
EPIX Essa Pharma Inc. 0.15% 677,005 $5.7M No change
PLRX Pliant Therapeutics Inc. 0.15% 384,996 $5.7M No change
BEAM Beam Therapeutics Inc. 0.12% 147,510 $4.9M Add +32.4%
VINCERX PHARMA INC 0.12% 891,719 $4.5M No change
KYTX Kyverna Therapeutics Inc. 0.11% 178,963 $4.4M New
SGMT Sagimet Biosciences Inc. Class A 0.11% 770,671 $4.2M Add +4.4%
GOSS Gossamer Bio Inc. 0.10% 3,266,960 $3.9M No change
ADAPY Adaptimmune Therapeutics-ADR 0.10% 2,425,468 $3.8M No change
ACRS Aclaris Therapeutics Inc. 0.09% 2,753,495 $3.4M Reduce -8.2%
CGEN Compugen Ltd. 0.08% 1,289,990 $3.3M No change
AMLX Amylyx Pharmaceuticals Inc. 0.07% 1,011,412 $2.9M Add +89.0%
BMEA Biomea Fusion Inc. 0.07% 181,147 $2.7M No change
NVAX Novavax Inc. 0.07% 537,625 $2.6M No change
CYPH Cypherpunk Technologies Inc. filed as LEAP THERAPEUTICS INC 0.06% 911,937 $2.4M Add +9.5%
SPRB Spruce Biosciences Inc. 0.05% 2,609,125 $2.1M No change
VIGL Vigil Neuroscience Inc. 0.04% 471,958 $1.6M No change
XLO Xilio Therapeutics Inc. 0.04% 1,440,759 $1.6M No change
RENEO PHARMACEUTICALS INC 0.03% 751,730 $1.2M No change
TLPH Talphera Inc. 0.01% 316,460 $326K No change

Options reported separately and not counted above: ALNY calls ($4.9M).

Other holdings (5): bonds, preferreds, convertibles and warrants · $9.0M (not counted above)
SecurityClassShares / PrincipalValueChange
GOSSAMER BIO INC (GOSS 5 06/01/27) NOTE 5.000% 6/0 · principal 9,573,000$3.8MNo change
TRAVERE THERAPEUTICS INC (TVTX 2.5 09/15/25) NOTE 2.500% 9/1 · principal 3,250,000$2.8MNo change
NEUROCRINE BIOSCIENCES (NBIX 2.25 05/15/24) NOTE 2.250% 5/1 · principal 1,000,000$1.8MNo change
NEVRO CORP (NVRO 2.75 04/01/25) NOTE 2.750% 4/0 · principal 500,000$474KNo change
NUVB.WS Nuvation Bio Inc. -CW27 *W EXP 02/10/202 134,028$41KNo change

Total filed on the 13F, all lines: $3.9B.

Portfolio Sells Q4 2023 → Q1 2024
KRTX Karuna Therapeutics Inc. Sold out 0.00% −4.03
CERE Cerevel Therapeutics Holding Reduce -79.5% 0.59% −2.21
HUM Humana Inc. Reduce -52.5% 1.30% −2.21
MRTX Mirati Therapeutics Inc. Sold out 0.00% −1.21
PODD Insulet Corp. Reduce -25.9% 1.40% −0.92
IMCR Immunocore Holdings PLC-ADR Reduce -11.0% 3.92% −0.58
IMGN Immunogen Inc. Sold out 0.00% −0.56
BPMC Blueprint Medicines Corp. Reduce -13.3% 6.04% −0.54
AMGN Amgen Inc. Sold out 0.00% −0.53
PEN Penumbra Inc. Reduce -6.0% 2.87% −0.47
ICVX Icosavax Inc. Sold out 0.00% −0.34
IMTX Immatics NV Reduce -54.7% 0.23% −0.26
NBIX Neurocrine Biosciences Inc. Reduce -11.8% 3.71% −0.19
RLAY Relay Therapeutics Inc. Sold out 0.00% −0.18
ACRS Aclaris Therapeutics Inc. Reduce -8.2% 0.09% +0.01
MLYS Mineralys Therapeutics Inc. Reduce -32.1% 0.26% +0.01
AGIO Agios Pharmaceuticals Inc. Reduce -18.0% 1.31% +0.13

Portfolio Buys Q4 2023 → Q1 2024
LLY Eli Lilly & Co. Add +48.6% 2.05% +1.04
MDGL Madrigal Pharmaceuticals Inc. Add +44.3% 1.95% +0.81
SGRY Surgery Partners Inc. New 0.75% +0.75
MRUS Merus NV Add +31.5% 1.32% +0.72
OSCR Oscar Health Inc. Class A Add +187.1% 0.80% +0.63
SWAV Shockwave Medical Inc. Add +12.5% 1.12% +0.55
VKTX Viking Therapeutics Inc. New 0.55% +0.55
CLDX Celldex Therapeutics Inc. Add +41.5% 1.47% +0.52
NVO Novo-Nordisk A/S-Spons ADR New 0.48% +0.48
PHVS Pharvaris NV New 0.44% +0.44
VERA Vera Therapeutics Inc. New 0.37% +0.37
CRNX Crinetics Pharmaceuticals Inc. New 0.35% +0.35
CRL Charles River Laboratories New 0.33% +0.33
DYN Dyne Therapeutics Inc. New 0.33% +0.33
ACHC Acadia Healthcare Co. Inc. Add +9.7% 2.38% +0.31
JSPR Jasper Therapeutics Inc. New 0.30% +0.30
DXCM Dexcom Inc. Add +0.1% 2.11% +0.28
AZTA Azenta Inc. Add +36.9% 1.07% +0.25
RVMD Revolution Medicines Inc. Add +27.4% 0.76% +0.24
NUVL Nuvalent Inc. Class A New 0.24% +0.24
IRTC Irhythm Holdings Inc. Add +11.8% 1.16% +0.23
MREO Mereo Biopharma Group PL-ADR Add +2.0% 0.68% +0.23
NMRA Neumora Therapeutics Inc. New 0.23% +0.23
INSP Inspire Medical Systems Inc. Add +31.8% 0.71% +0.22
AKRO Akero Therapeutics Inc. Add +20.2% 0.84% +0.21
MGNX Macrogenics Inc. Add +10.7% 0.49% +0.21
ELVN Enliven Therapeutics Inc. New 0.19% +0.19
CGON CG Oncology Inc. New 0.19% +0.19
APLT Applied Therapeutics Inc. Add +67.3% 0.26% +0.19
PHR Phreesia Inc. Add +7.2% 1.44% +0.18
BHVN Biohaven Ltd. New 0.18% +0.18
AUTL Autolus Therapeutics PLC New 0.17% +0.17
GPCR Structure Therapeutics Inc. Add +43.9% 0.45% +0.16
KYTX Kyverna Therapeutics Inc. New 0.11% +0.11
EVH Evolent Health Inc. Class A Add +0.7% 3.33% +0.10
FOCL Edap TMS SA -ADR Add +6.4% 0.28% +0.10
TVTX Travere Therapeutics Inc. Add +23.6% 0.67% +0.06
AUPH Aurinia Pharmaceuticals Inc. Add +178.8% 0.15% +0.06
BEAM Beam Therapeutics Inc. Add +32.4% 0.12% +0.05
RARE Ultragenyx Pharmaceutical Inc. Add +1.2% 2.11% +0.04
WRBY Warby Parker Inc. Class A Add +2.5% 0.72% +0.01
SGMT Sagimet Biosciences Inc. Class A Add +4.4% 0.11% +0.01
EXAS Exact Sciences Corp. Add +4.0% 1.86% −0.00
LEGN Legend Biotech Corp.-ADR Add +1.4% 0.71% −0.02
CYPH Cypherpunk Technologies Inc. Add +9.5% 0.06% −0.02
FOLD Amicus Therapeutics Inc. Add +8.3% 0.35% −0.03
BCRX Biocryst Pharmaceuticals Inc. Add +6.9% 0.45% −0.03
IMVT Immunovant Inc. Add +17.0% 0.95% −0.08
ACCD Accolade Inc. Add +1.6% 0.95% −0.09
AMLX Amylyx Pharmaceuticals Inc. Add +89.0% 0.07% −0.12

Options Activity Q4 2023 → Q1 2024
INHIBRX INC call Sold out 301,400 $11.5Mbefore exit
ALNY Alnylam Pharmaceuticals Inc. call New 32,500 $4.9M

Calls and puts are listed by the shares they cover; their value is not part of the stock holdings above.

All Filings

QuarterPositions13F Reported ValueTop Holdings
Q2 2026 104$2.0BRVMD, TVTX, LLY, MDGL, MIRM
Q1 2026 100$1.7BRVMD, LLY, MDGL, MIRM, ARGX
Q4 2025 96$1.9BLLY, RVMD, ARGX, TVTX, MDGL
Q3 2025 90$1.7BARGX, LLY, RYTM, MDGL, RVMD
Q2 2025 91$1.6BARGX, LLY, MRUS, RYTM, INSM
Q1 2025 94$1.7BARGX, LLY, BPMC, MDGL, UNH
Q4 2024 104$2.6BARGX, ISRG, LLY, NBIX, BPMC
Q3 2024 106$3.1BUNH, ISRG, ARGX, LLY, RARE
Q2 2024 106$3.3BBPMC, UNH, ISRG, NBIX, LLY
Q1 2024 108$3.9BBPMC, IMCR, NBIX, EVH, ISRG