SEC 13F Intelligence

Managers / Q3 2023 · view latest →

Rock Springs Capital Management LP

CIK 0001595725 · 650 SOUTH EXETER STREET, SUITE 1070, BALTIMORE, MD, 21202 · 4102200129

Reported Value
$3.7B
Q3 2023
Positions
120
Filings on Record
30
2019–present window
Filed
Nov 14, 2023
original filing

Summary

Rock Springs Capital Management LP reported $3.7B in U.S.-listed holdings across 120 positions for Q3 2023.

Its largest position, HUM, represents 5.7% of the portfolio.

Compared with Q2 2023, the fund opened 7 new positions and exited 10.

Portfolio Metrics

Turnover
+5.9%
vs prior filed quarter
Top-10 Concentration
+36.0%
share of reported value
Largest Position
+5.7%
Humana
New / Exited
7 / 10
positions this quarter

Methodology: turnover is min(value bought, value sold) ÷ average reported value across the two quarters — value-based, so market moves inflate it slightly versus a share-based measure. Concentration and largest position are shares of the filing’s total reported value, options excluded. New/exited counts compare against the prior filed quarter. All figures derive solely from the fund’s 13F filings.

Reported Value by Quarter

13F Reported Value
Q4 ’18: $2.1BQ4 ’18Q1 ’19: $2.6BQ2 ’19: $2.8BQ3 ’19: $2.5BQ4 ’19: $3.2BQ4 ’19Q1 ’20: $2.4BQ2 ’20: $3.6BQ3 ’20: $3.9BQ4 ’20: $4.7BQ4 ’20Q1 ’21: $4.6BQ2 ’21: $5.1BQ3 ’21: $4.8BQ4 ’21: $4.3BQ4 ’21Q1 ’22: $4.0BQ2 ’22: $3.4BQ3 ’22: $3.9BQ4 ’22: $4.2BQ4 ’22Q1 ’23: $4.2BQ2 ’23: $4.2BQ3 ’23: $3.7BQ4 ’23: $4.1BQ4 ’23Q1 ’24: $3.9BQ2 ’24: $3.3BQ3 ’24: $3.1BQ4 ’24: $2.6BQ4 ’24Q1 ’25: $1.7BQ2 ’25: $1.6BQ3 ’25: $1.7BQ4 ’25: $2.0BQ4 ’25Q1 ’26: $1.7Bfilingsflow.com

Portfolio Composition

By security type
Common Stock: 76.6%Other: 12.8%ADR: 9.7%ETP: 0.7%US DOMESTIC: 0.2%Other: 0.0%
  • Common Stock · 76.6% · $2.9B
  • Other · 12.8% · $476M
  • ADR · 9.7% · $363M
  • ETP · 0.7% · $26M
  • US DOMESTIC · 0.2% · $8M
  • Other · 0.0% · $13,403

Quarter-over-Quarter Changes full breakdown →

vs Q2 2023 (amended baseline)

IssuerMoveShare ΔShares nowValue ΔValue now
IMVTIMMUNOVANT INCNEW+644.3K644.3K+$25M$25M
AMGNAMGEN INCNEW+68.0K68.0K+$18M$18M
ABOSACUMEN PHARMACEUTICALS INCNEW+2.81M2.81M+$12M$12M
INSPINSPIRE MED SYS INCNEW+44.5K44.5K+$9M$9M
SGMTSAGIMET BIOSCIENCES INCNEW+738.4K738.4K+$6M$6M
SYREAEGLEA BIOTHERAPEUTICS INCNEW+136.6K136.6K+$2M$2M
DP8CERVOMED INCNEW+80.0K80.0K+$369,752$369,752
IMGNEURIMMUNOGEN INCADDED+646.7K759.4K+$10M$12M

Value changes conflate price moves with buying and selling — share changes are the real signal. Share counts are not split-adjusted.

Holdings — Q3 2023

50 positions
Export to Excel
#IssuerClass% PortfolioValue ↓Shares
1HUMHUMANA INChistory →COM5.69%$212M436.5K
2IMCRIMMUNOCORE HLDGS PLChistory →ADS4.09%$153M2.94M
3AGILON HEALTH INCCOM3.95%$147M8.29M
4NBIXNEUROCRINE BIOSCIENCES INChistory →COM3.72%$139M1.24M
52655787DBLUEPRINT MEDICINES CORPhistory →COM3.61%$135M2.69M
6ARGXARGENX SEhistory →SPONSORED ADR3.41%$127M259.0K
7PENPENUMBRA INChistory →COM3.26%$122M503.8K
8UNHUNITEDHEALTH GROUP INChistory →COM3.11%$116M230.0K
9EVHEVOLENT HEALTH INChistory →CL A2.82%$105M3.87M
10ISRGINTUITIVE SURGICAL INChistory →COM NEW2.34%$87M298.5K
11KARUNA THERAPEUTICS INCCOM2.29%$85M505.4K
12IDXXIDEXX LABS INChistory →COM2.28%$85M194.5K
13SGENUSDSEAGEN INChistory →COM2.27%$85M400.2K
14WSTWEST PHARMACEUTICAL SVSC INChistory →COM2.03%$76M202.0K
15AKROAKERO THERAPEUTICS INChistory →COM1.92%$72M1.42M
16EXKEXACT SCIENCES CORPhistory →COM1.86%$69M1.02M
17AGIOAGIOS PHARMACEUTICALS INChistory →COM1.80%$67M2.71M
18AFWALIGN TECHNOLOGY INChistory →COM1.77%$66M217.0K
19ACHCACADIA HEALTHCARE COMPANY INhistory →COM1.71%$64M908.0K
20BSXBOSTON SCIENTIFIC CORPhistory →COM1.64%$61M1.16M
21PODDINSULET CORPhistory →COM1.62%$61M380.0K
22MIRMMIRUM PHARMACEUTICALS INChistory →COM1.54%$58M1.82M
23CEREVEL THERAPEUTICS HLDNG ICOM1.48%$55M2.53M
24DC4DEXCOM INChistory →COM1.46%$54M584.0K
25RAREULTRAGENYX PHARMACEUTICAL INhistory →COM1.41%$53M1.48M
26ALNYALNYLAM PHARMACEUTICALS INChistory →COM1.33%$49M279.5K
27MRTXEURMIRATI THERAPEUTICS INChistory →COM1.32%$49M1.13M
28SRPTSAREPTA THERAPEUTICS INChistory →COM1.27%$48M392.0K
29EWEDWARDS LIFESCIENCES CORPhistory →COM1.20%$45M647.3K
30FRPTFRESHPET INChistory →COM1.17%$44M662.5K
31XENEXENON PHARMACEUTICALS INChistory →COM1.08%$40M1.18M
32ASCENDIS PHARMA A/SSPONSORED ADR1.07%$40M425.5K
33RYTMRHYTHM PHARMACEUTICALS INChistory →COM0.98%$37M1.60M
34PHRPHREESIA INChistory →COM0.89%$33M1.78M
35IRTCIRHYTHM TECHNOLOGIES INChistory →COM0.89%$33M350.8K
36PCRXPACIRA BIOSCIENCES INChistory →COM0.87%$32M1.06M
37ACCDUSDACCOLADE INChistory →COM0.83%$31M2.91M
38LEGNLEGEND BIOTECH CORPhistory →SPONSORED ADS0.82%$31M458.3K
39ZLABZAI LAB LTDhistory →ADR0.81%$30M1.24M
40PROTHENA CORP PLCSHS0.79%$30M614.3K
41HORIZON THERAPEUTICS PUB LSHS0.79%$30M255.5K
42SWAVUSDSHOCKWAVE MED INChistory →COM0.79%$29M147.5K
43ABCAM PLCADS0.77%$29M1.27M
44MDGLMADRIGAL PHARMACEUTICALS INChistory →COM0.77%$29M196.4K
45AMLXAMYLYX PHARMACEUTICALS INChistory →COM0.76%$28M1.55M
46ACRSACLARIS THERAPEUTICS INChistory →COM0.73%$27M3.96M
47DVAXDYNAVAX TECHNOLOGIES CORPhistory →COM NEW0.72%$27M1.81M
48SELECT SECTOR SPDR TRSBI HEALTHCARE0.69%$26M200.0K
49LFSTLIFESTANCE HEALTH GROUP INChistory →COM0.68%$25M3.67M
50IMVTIMMUNOVANT INChistory →COM0.66%$25M644.3K

Filing History

QuarterReported ValuePositionsFiledTypeLinks
Q1 2026$1.7B100May 15, 202613F-HRchanges · EDGAR ↗
Q4 2025$2.0B99Feb 17, 202613F-HRchanges · EDGAR ↗
Q3 2025$1.7B93Nov 14, 202513F-HRchanges · EDGAR ↗
Q2 2025$1.6B93Aug 14, 202513F-HRchanges · EDGAR ↗
Q1 2025$1.7B96May 15, 202513F-HRchanges · EDGAR ↗
Q4 2024$2.6B107Feb 14, 202513F-HRchanges · EDGAR ↗
Q3 2024$3.1B109Nov 14, 202413F-HRchanges · EDGAR ↗
Q2 2024$3.3B112Aug 14, 202413F-HRchanges · EDGAR ↗
Q1 2024$3.9B114May 15, 202413F-HRchanges · EDGAR ↗
Q4 2023$4.1B104Feb 14, 202413F-HRchanges · EDGAR ↗
Q3 2023$3.7B120Nov 14, 202313F-HRchanges · EDGAR ↗
Q2 2023$4.2B123Aug 14, 202313F-HRchanges · EDGAR ↗
Q1 2023$4.2B121May 15, 202313F-HRchanges · EDGAR ↗
Q4 2022$4.2B120Feb 14, 202313F-HRchanges · EDGAR ↗
Q3 2022$3.9B128Nov 14, 202213F-HRchanges · EDGAR ↗
Q2 2022$3.4B131Aug 15, 202213F-HRchanges · EDGAR ↗
Q1 2022$4.0B135May 16, 202213F-HRchanges · EDGAR ↗
Q4 2021$4.3B136Feb 14, 202213F-HRchanges · EDGAR ↗
Q3 2021$4.8B153Nov 15, 202113F-HRchanges · EDGAR ↗
Q2 2021$5.1B156Aug 16, 202113F-HRchanges · EDGAR ↗
Q1 2021$4.6B151May 17, 202113F-HRchanges · EDGAR ↗
Q4 2020$4.7B155Feb 16, 202113F-HRchanges · EDGAR ↗
Q3 2020$3.9B148Nov 16, 202013F-HRchanges · EDGAR ↗
Q2 2020$3.6B143Aug 14, 202013F-HRchanges · EDGAR ↗
Q1 2020$2.4B131May 15, 202013F-HRchanges · EDGAR ↗
Q4 2019$3.2B130Feb 14, 202013F-HRchanges · EDGAR ↗
Q3 2019$2.5B138Nov 14, 201913F-HRchanges · EDGAR ↗
Q2 2019$2.8B135Aug 14, 201913F-HRchanges · EDGAR ↗
Q1 2019$2.6B131May 15, 201913F-HRchanges · EDGAR ↗
Q4 2018$2.1B133Feb 14, 201913F-HRchanges · EDGAR ↗

13F filings are due up to 45 days after quarter end, so holdings shown here lag the fund’s current book. Source: original SEC filing on EDGAR ↗.