ROCK SPRINGS CAPITAL MANAGEMENT LP
Q1 2023 Form 13-F
BALTIMORE, MARYLAND
CIK 0001595725
· CRD 168648
· SEC-registered investment adviser
$4.2B Reported Value Total
ROCK SPRINGS CAPITAL reports 6 total accounts under management (AUM). There are 6 discretionary accounts valued at $5,716,429,633, and 0 non-discretionary accounts.
Source: Form ADV filed * Note that certain holdings are exempt from Form 13-F reporting, so the AUM totals may be greater than the Form 13-F total.
Private funds (Form ADV)
2 funds
· $2.4B gross asset value
Hedge Fund: $2.4B
Source: Form ADV filed 2026-03-24
Reported value
$4.2B
Quarter over quarter
+0.0%
Holdings
116
Top-10 concentration
34.6%
Key People
Form ADV owners & control persons
Gordon Margraf ("mark") Bussard
MEMBER/LIMITED PARTNER
Kris Harlan Jenner
MEMBER/LIMITED PARTNER
Nnamdi C Etoh
CHIEF FINANCIAL OFFICER
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13F Metrics
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Q1 2023 13F record
Q1 2023 13F filing summary
| Period of report | March 31, 2023 |
|---|---|
| Filed | May 15, 2023 |
| Form | 13F-HR |
| Reported value | $4.2B |
| Positions | 116 |
| Change in reported value | +0.9% |
| New positions | 3 |
| Exited positions | 3 |
| Position turnover | 5.0% |
| Top-10 concentration | 34.6% |
13F filings by quarter
| Quarter | Positions | Value |
|---|---|---|
|
Q2 2026 13F
Filed Aug 14, 2026
|
104 | $2.0B |
|
Q1 2026 13F
Filed May 15, 2026
|
100 | $1.7B |
|
Q4 2025 13F
Filed Feb 17, 2026
|
97 | $2.0B |
|
Q3 2025 13F
Filed Nov 14, 2025
|
91 | $1.7B |
|
Q2 2025 13F
Filed Aug 14, 2025
|
92 | $1.6B |
|
Q1 2025 13F
Filed May 15, 2025
|
95 | $1.7B |
|
Q4 2024 13F
Filed Feb 14, 2025
|
105 | $2.6B |
|
Q3 2024 13F
Filed Nov 14, 2024
|
107 | $3.1B |
|
Q2 2024 13F
Filed Aug 14, 2024
|
107 | $3.3B |
|
Q1 2024 13F
Filed May 15, 2024
|
109 | $3.9B |
|
Q4 2023 13F
Filed Feb 14, 2024
|
99 | $4.1B |
|
Q3 2023 13F
Filed Nov 14, 2023
|
116 | $3.7B |
|
Q2 2023 13F
Filed Aug 14, 2023
|
119 | $4.2B |
|
Q1 2023 13F
Filed May 15, 2023
|
116 | $4.2B |
|
Q4 2022 13F
Filed Feb 14, 2023
|
116 | $4.2B |
|
Q3 2022 13F
Filed Nov 14, 2022
|
123 | $3.9B |
|
Q2 2022 13F
Filed Aug 15, 2022
|
125 | $3.4B |
|
Q1 2022 13F
Filed May 16, 2022
|
128 | $4.0B |
|
Q4 2021 13F
Filed Feb 14, 2022
|
128 | $4.3B |
|
Q3 2021 13F
Filed Nov 15, 2021
|
145 | $4.8B |
31 earlier quarters on file — choose one from the quarter menu above.
Top 20 holdings · Q1 2023
| # | Holding | Reported value | % of portfolio |
|---|---|---|---|
| 1 | HUM HUMANA INC | $207.0M | 4.94% |
| 2 | AGL AGILON HEALTH INC | $187.2M | 4.47% |
| 3 | PODD INSULET CORP | $171.2M | 4.08% |
| 4 | IMCR IMMUNOCORE HLDGS PLC | $148.4M | 3.54% |
| 5 | ARGX ARGENX SE | $130.4M | 3.11% |
| 6 | UNH UNITEDHEALTH GROUP INC | $127.6M | 3.04% |
| 7 | EVH EVOLENT HEALTH INC | $123.4M | 2.94% |
| 8 | NBIX NEUROCRINE BIOSCIENCES INC | $122.5M | 2.92% |
| 9 | PEN PENUMBRA INC | $120.8M | 2.88% |
| 10 | RXDX PROMETHEUS BIOSCIENCES INC | $110.7M | 2.64% |
| 11 | IDXX IDEXX LABS INC | $103.8M | 2.48% |
| 12 | BPMC BLUEPRINT MEDICINES CORP | $91.5M | 2.18% |
| 13 | KRTX KARUNA THERAPEUTICS INC | $89.6M | 2.14% |
| 14 | MDGL MADRIGAL PHARMACEUTICALS INC | $84.3M | 2.01% |
| 15 | ALGN ALIGN TECHNOLOGY INC | $82.6M | 1.97% |
| 16 | SGEN SEAGEN INC | $81.0M | 1.93% |
| 17 | HZNP HORIZON THERAPEUTICS PUB L | $80.8M | 1.93% |
| 18 | ISRG INTUITIVE SURGICAL INC | $76.3M | 1.82% |
| 19 | WST WEST PHARMACEUTICAL SVSC INC | $70.0M | 1.67% |
| 20 | ALNY ALNYLAM PHARMACEUTICALS INC | $69.1M | 1.65% |
Values as reported on the Q1 2023 Form 13F. Every position is in the holdings table below.