Rock Springs Capital Management Lp
- Regulatory AUM
- $2.4B
- Discretionary
- $2.4B
- Clients
- 6
- Avg AUM / client
- $404M
- Accounts
- 6
- Employees
- 17
AUM over time
Annual snapshots from Form ADV filings · as of Mar 24, 2026
Investments (13F portfolio — 100 positions, $1,696,654,121)
13F period Mar 31, 2026| # | Issuer | Class | Value | Shares | % of 13F | % of AUM |
|---|---|---|---|---|---|---|
| 1 | Revolution Medicines Inc | COM | $117,620,471 | 1,209,465 | 6.93% | 4.85% |
| 2 | Eli Lilly & Co | COM | $90,781,299 | 98,700 | 5.35% | 3.74% |
| 3 | Madrigal Pharmaceuticals Inc | COM | $89,512,847 | 170,999 | 5.28% | 3.69% |
| 4 | Mirum Pharmaceuticals Inc | COM | $74,947,340 | 811,294 | 4.42% | 3.09% |
| 5 | Argenx Se | SPONSORED ADR | $71,929,625 | 98,500 | 4.24% | 2.96% |
| 6 | Rhythm Pharmaceuticals Inc | COM | $59,987,384 | 689,748 | 3.54% | 2.47% |
| 7 | Insmed Inc | COM PAR $.01 | $51,394,336 | 314,300 | 3.03% | 2.12% |
| 8 | Ascendis Pharma A/S | SPONSORED ADR | $44,373,620 | 194,000 | 2.62% | 1.83% |
| 9 | Xenon Pharmaceuticals Inc | COM | $44,369,613 | 763,020 | 2.62% | 1.83% |
| 10 | Travere Therapeutics Inc | COM | $43,910,013 | 1,477,954 | 2.59% | 1.81% |
| 11 | Kymera Therapeutics Inc | COM | $41,384,386 | 496,871 | 2.44% | 1.71% |
| 12 | Penumbra Inc | COM | $39,568,585 | 120,500 | 2.33% | 1.63% |
| 13 | Intuitive Surgical Inc | COM NEW | $37,801,180 | 82,000 | 2.23% | 1.56% |
| 14 | Scholar Rock Hldg Corp | COM | $36,369,355 | 739,816 | 2.14% | 1.5% |
| 15 | Enliven Therapeutics Inc | COM | $32,398,800 | 826,500 | 1.91% | 1.34% |
| 16 | Boston Scientific Corp | COM | $32,335,075 | 515,300 | 1.91% | 1.33% |
| 17 | Irhythm Holdings Inc | COM | $30,891,735 | 261,750 | 1.82% | 1.27% |
| 18 | Structure Therapeutics Inc | SPONSORED ADS | $30,858,459 | 640,217 | 1.82% | 1.27% |
| 19 | Agios Pharmaceuticals Inc | COM | $27,035,684 | 799,163 | 1.59% | 1.11% |
| 20 | Ultragenyx Pharmaceutical In | COM | $25,533,294 | 1,218,773 | 1.5% | 1.05% |
| 21 | Alnylam Pharmaceuticals Inc | COM | $24,484,380 | 74,000 | 1.44% | 1.01% |
| 22 | Cogent Biosciences Inc | COM | $24,023,726 | 624,155 | 1.42% | 0.99% |
| 23 | Tenet Healthcare Corp | COM NEW | $23,588,750 | 125,000 | 1.39% | 0.97% |
| 24 | Dexcom Inc | COM | $22,331,680 | 355,600 | 1.32% | 0.92% |
| 25 | Celldex Therapeutics Inc New | COM NEW | $20,626,564 | 650,270 | 1.22% | 0.85% |
Top 25 of 100 positions from the manager's latest Form 13F · source filing (EDGAR) ↗. 13F covers long US-listed positions only. "% of AUM" is share of the firm's total regulatory AUM (Form ADV Item 5.F).
Who they serve
| Client type | Clients | AUM | % of AUM |
|---|---|---|---|
| Pooled investment vehicles (non-investment companies) | 6 | $2.4B | 100.0% |
Private funds (2)
Reported in Form ADV Section 7.B.(1), filing of Mar 2024 · $5.8B combined gross assets
| Fund | Type | Domicile | Gross assets | Owners |
|---|---|---|---|---|
| Rock Springs Capital Master Fund Lp master | Hedge Fund | Cayman Islands | $5.5B | 635 |
| Four Pines Master Fund Lp master | Hedge Fund | Cayman Islands | $264M | 25 |
People (5)
| Name | Role / title | Credentials | With firm since | Ownership |
|---|---|---|---|---|
| Bussard, Gordon, Margraf ("Mark") | Member/Limited Partner | Mar 2013 (13y) | 25% – 50% | |
| Jenner, Kris, Harlan | Member/Limited Partner | Mar 2013 (13y) | 25% – 50% | |
| Mcphail, Graham, Morgan | Member/Limited Partner | Mar 2013 (13y) | 25% – 50% | |
| Etoh, Nnamdi, C | Chief Financial Officer | Jan 2021 (6y) | Less than 5% | |
| O'connor, Aidan, Hugh | Chief Compliance Officer And General Counsel | Oct 2022 (4y) | Less than 5% |
Entity owners (Schedule A/B)
| Entity | Title / status | Since | Sch. | Ownership |
|---|---|---|---|---|
| Rock Springs Capital Llc | General Partner | Mar 2013 | A | Less than 5% |
Undisclosed: 0% – 25% of the firm is not attributable from the filed Schedule A bands.
Roster from the IAPD representatives feed; ownership and acquisition dates from Form ADV Schedule A/B. "Since" is the earliest filed registration or acquisition date.
Private funds (2, $5.8B gross assets)
| Fund | Type | Gross assets | Min. investment | Owners |
|---|---|---|---|---|
| Rock Springs Capital Master Fund Lp | Hedge Fund | $5.5B | $10.0M | 635 |
| Four Pines Master Fund Lp | Hedge Fund | $264M | $10.0M | 25 |
From Form ADV Section 7.B private fund reporting.
Documents (1 archived)
| Form | Period | Size | |
|---|---|---|---|
| Form ADV (full filing) | 03/24/2026 | 1.59 MB | View · PDF · Source ↗ |
Archived copies of the firm's regulatory filings, versioned by content hash.
Disciplinary disclosures
No disciplinary events reported on the firm's latest Form ADV filing.
How they charge
- • Percentage of assets under management
- • Performance-based fees
Services
- • Portfolio management for pooled investment vehicles
Custody
Firm reports it does not have custody of client funds or securities (Item 9.A).
No custodian data reported or mined yet.
Source
All data on this page comes from this firm's Form ADV filings, reproduced without modification. Latest filing: Mar 24, 2026.
View current Form ADV (SEC/IAPD) ↗