Arkolith/Funds/Rock Springs Capital Management LP

Rock Springs Capital Management LP

CIK 1595725
Holdings as of Jun 30, 2026·disclosed Aug 14, 2026·~45-day 13F lag·13F-HR
Active Filer

Rock Springs Capital Management LP holds a focused book of 104 stocks worth $2.0B as of Q2 2026 (disclosed Aug 14, 2026, a ~45-day 13F lag). This quarter they opened Ascendis Pharma A/s and trimmed Revolution Medicines Inc. Their largest long position is Revolution Medicines Inc at 10% of the equity book.

Opened
25
bought for the first time
Added to
40
already held, bought more
Trimmed
30
sold some, still holds it
Sold out
13
exited the position entirely

Concentration

Top-heavy: focused book

Top 5 holdings
31%
Top 10 holdings
44%
Top 20 holdings
60%

Share of the disclosed book in its largest positions. A higher top-5 share means a more concentrated, higher-conviction portfolio.

Direct sector allocation

97% mapped to company sectors

Health Care
95%
ETF / fund or unclassified
3%
Industrials
2%
Information Technology
0%
Consumer Staples
0%
Materials
0%

Direct operating-company sectors from our SIC-based security master. ETF/fund and unclassified holdings stay visible separately; this is not ETF look-through exposure.

Biggest moves: latest quarter

Estimated $ traded · quarter-end prices, no cost basis

Bought
Trimmed / exited

Funds with the most overlap

Other tracked managers holding the same core names as Rock Springs Capital Management LP

Manager / fundShared namesTheir $ in those
GEODE CAPITAL MANAGEMENT, LLC80 / 80$59.6B
MORGAN STANLEY75 / 80$38.2B
UBS Group AG75 / 80$12.5B
BlackRock, Inc.74 / 80$176.2B
STATE STREET CORP74 / 80$110.5B
FMR LLC74 / 80$73.1B
WELLS FARGO & COMPANY/MN74 / 80$8.6B
BNP PARIBAS FINANCIAL MARKETS74 / 80$4.4B

Ranked by how many of Rock Springs Capital Management LP's top 80 disclosed names each fund also holds: a cross-fund conviction signal from the latest 13F of every tracked manager.

Holdings: largest first

Bars show each stock's share of the portfolio. Click a row for its position history.

104 positions
#SecurityValueShares% PortLast moveHistory
1Revolution Medicines Inc
COM
$207.0M1.11M
10.1%
▼−8.6%
Reduced · −104K sh
2Travere Therapeutics Inc
COM
$123.8M2.18M
6.0%
▲+47%
Added · +701K sh
3Eli Lilly & Co
COM
$118.4M98.7K
5.8%
—Held
4Madrigal Pharmaceuticals Inc
COM
$94.0M175.0K
4.6%
▲+2.3%
Added · +4K sh
5Mirum Pharmaceuticals Inc
COM
$93.4M798.1K
4.6%
▼−1.6%
Reduced · −13K sh
6Rhythm Pharmaceuticals Inc
COM
$76.9M692.6K
3.8%
▲+0.4%
Added · +3K sh
7Kymera Therapeutics Inc
COM
$52.0M453.2K
2.5%
▼−8.8%
Reduced · −44K sh
8Argenx SE
SPONSORED ADR
$48.9M52.8K
2.4%
▼−46%
Reduced · −46K sh
9Ascendis Pharma A/s
ORD SHS
$45.0M168.8K
2.2%
▲New
New position
10Xenon Pharmaceuticals Inc
COM
$41.3M683.9K
2.0%
▼−10%
Reduced · −79K sh
11Scholar Rock Hldg Corp
COM
$39.3M715.5K
1.9%
▼−3.3%
Reduced · −24K sh
12Insmed Inc
COM PAR $.01
$38.6M362.1K
1.9%
▲+15%
Added · +48K sh
13Penumbra Inc
COM
$36.5M115.8K
1.8%
▼−3.9%
Reduced · −5K sh
14Structure Therapeutics Inc
SPONSORED ADS
$34.4M640.3K
1.7%
▲~0%
Added · +100 sh
15Ultragenyx Pharmaceutical In
COM
$32.3M967.9K
1.6%
▼−21%
Reduced · −251K sh
16Irhythm Holdings Inc
COM
$32.1M269.6K
1.6%
▲+3.0%
Added · +8K sh
17Intuitive Surgical Inc
COM NEW
$30.4M76.5K
1.5%
▼−6.8%
Reduced · −6K sh
18Agilon Health Inc
COM NEW
$28.1M262.6K
1.4%
▲+1.0%
Added · +3K sh
19Unitedhealth Group Inc
COM
$26.5M63.8K
1.3%
▲+20%
Added · +11K sh
20Celldex Therapeutics Inc New
COM NEW
$26.0M699.1K
1.3%
▲+7.5%
Added · +49K sh
21Erasca Inc
COM
$25.7M1.40M
1.3%
▲+27%
Added · +299K sh
22Neurocrine Biosciences Inc
COM
$24.4M144.8K
1.2%
▼−3.8%
Reduced · −6K sh
23Enliven Therapeutics Inc
COM
$23.6M464.6K
1.2%
▼−44%
Reduced · −362K sh
24Tenet Healthcare Corp
COM NEW
$23.4M125.0K
1.1%
—Held
25Dexcom Inc
COM
$23.1M343.0K
1.1%
▼−3.5%
Reduced · −13K sh
26Aclaris Therapeutics Inc
COM
$22.9M4.33M
1.1%
▼−3.2%
Reduced · −142K sh
27Minimed Group Inc
COM
$22.7M1.52M
1.1%
▲+44%
Added · +465K sh
28Boston Scientific Corp
COM
$22.6M528.5K
1.1%
▲+2.6%
Added · +13K sh
29Pharvaris N V
COM
$22.4M648.3K
1.1%
▲+0.4%
Added · +3K sh
30Avalyn Pharmaceuticals Inc
COM SHS
$21.8M662.9K
1.1%
▲New
New position
31Hemab Therapeutics Hldgs Inc
COM SHS
$21.1M575.4K
1.0%
▲New
New position
32Dyne Therapeutics Inc
COM
$20.9M942.2K
1.0%
▼−3.1%
Reduced · −30K sh
33Alnylam Pharmaceuticals Inc
COM
$20.1M66.8K
1.0%
▼−9.8%
Reduced · −7K sh
34Cogent Biosciences Inc
COM
$20.0M515.9K
1.0%
▼−17%
Reduced · −108K sh
35Agios Pharmaceuticals Inc
COM
$19.8M532.6K
1.0%
▼−33%
Reduced · −267K sh
36Newamsterdam Pharma Company
ORDINARY SHARES
$19.7M582.7K
1.0%
▼−1.0%
Reduced · −6K sh
37Vera Therapeutics Inc
CL A
$18.3M427.6K
0.9%
▼−15%
Reduced · −76K sh
38Tarsus Pharmaceuticals Inc
COM
$17.4M277.1K
0.9%
▲+23%
Added · +52K sh
39Heartflow Inc
COM
$16.8M573.5K
0.8%
▲+0.2%
Added · +1K sh
40MBX Biosciences Inc
COM
$16.5M298.2K
0.8%
▲+3.5%
Added · +10K sh
41Cytokinetics Inc
COM NEW
$16.0M188.0K
0.8%
▲+314%
Added · +143K sh
42Bicara Therapeutics Inc
COM
$15.9M535.3K
0.8%
▲+9.4%
Added · +46K sh
43Parabilis Medicines Inc
COM
$15.8M578.0K
0.8%
▲New
New position
44Zai Lab Ltd
ADR
$15.5M814.7K
0.8%
—Held
45Danaher Corp Del
COM
$14.5M76.3K
0.7%
▲+24%
Added · +15K sh
46Tango Therapeutics Inc
COM
$14.3M456.6K
0.7%
▲+18%
Added · +70K sh
47Evolent Health Inc
CL A
$13.6M2.50M
0.7%
▼−6.5%
Reduced · −175K sh
48PTC Therapeutics Inc
COM
$13.2M162.3K
0.6%
▲+0.3%
Added · +500 sh
49Mineralys Therapeutics Inc
COM
$13.1M485.0K
0.6%
▲+10%
Added · +45K sh
50Zenas Biopharma Inc
COM
$12.7M502.1K
0.6%
—Held
Showing 50 of 104 positions
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Filing history

As-of date vs the date the SEC received each filing

QuarterAs ofFiledPositionsValueForm
Q2 2026Jun 30, 2026Aug 14, 2026104$2.0B13F-HR
Q1 2026Mar 31, 2026May 15, 2026100$1.7B13F-HR
Q4 2025Dec 31, 2025Feb 17, 202699$2.0B13F-HR
Q3 2025Sep 30, 2025Nov 14, 202593$1.7B13F-HR
Q2 2025Jun 30, 2025Aug 14, 202593$1.6B13F-HR
Q1 2025Mar 31, 2025May 15, 202596$1.7B13F-HR
Q4 2024Dec 31, 2024Feb 14, 2025107$2.6B13F-HR
Q3 2024Sep 30, 2024Nov 14, 2024109$3.1B13F-HR
Q2 2024Jun 30, 2024Aug 14, 2024112$3.3B13F-HR
Q1 2024Mar 31, 2024May 15, 2024114$3.9B13F-HR
Q4 2023Dec 31, 2023Feb 14, 2024104$4.1B13F-HR
Q3 2023Sep 30, 2023Nov 14, 2023120$3.7B13F-HR
Q2 2023Jun 30, 2023Aug 14, 2023123$4.2B13F-HR
Q1 2023Mar 31, 2023May 15, 2023121$4.2B13F-HR
Q4 2022Dec 31, 2022Feb 14, 2023120$4.2B13F-HR
Q3 2022Sep 30, 2022Nov 14, 2022128$3.9B13F-HR
Q2 2022Jun 30, 2022Aug 15, 2022131$3.4B13F-HR
Q1 2022Mar 31, 2022May 16, 2022135$4.0B13F-HR
Q4 2021Dec 31, 2021Feb 14, 2022136$4.3B13F-HR
Q3 2021Sep 30, 2021Nov 15, 2021153$4.8B13F-HR
Q2 2021Jun 30, 2021Aug 16, 2021156$5.1B13F-HR
Q1 2021Mar 31, 2021May 17, 2021151$4.6B13F-HR
Q4 2020Dec 31, 2020Feb 16, 2021155$4.7B13F-HR
Q3 2020Sep 30, 2020Nov 16, 2020148$3.9B13F-HR

Data source

Holdings from SEC EDGAR 13F-HR filings, updated quarterly, filed up to 45 days after quarter-end. Public domain. The book and weighting are long equity only; disclosed put/call options are listed separately and excluded from those totals. Price-derived performance is withheld until the price-source policy and freshness gate are green.