Institutional Manager · CIK 0001595725
Rock Springs Capital Management LP
Baltimore, MD · File #028-16048
Latest AUM
$1.95B
Positions
99
Top-10 Concentration
45.0%
Filings
9
Portfolio Value Over Time
2024-03
2024-06
2024-09
2024-12
2025-03
2025-06
2025-09
2025-12
Biggest QoQ Changes
Ranked by conviction flow (share change × current price) so mark-to-market moves don't dominate. Price effect column shows how much of the $ change was just the stock moving.
| Action | Issuer | Ticker / CUSIP | Δ Shares | Flow ($) | Price Effect |
|---|---|---|---|---|---|
| EXITED | MERUS N V | N5749R100 | -597,051 | -$56.2M | $0 |
| REDUCE | ARGENX SE | ARGX | -39,500 | -$33.2M | +$14.8M |
| EXITED | AKERO THERAPEUTICS INC | 00973Y108 | -626,526 | -$29.7M | $0 |
| REDUCE | NEWAMSTERDAM PHARMA COMPANY | NAMSW | -564,329 | -$19.8M | +$4.0M |
| REDUCE | STRUCTURE THERAPEUTICS INC | GPCR | -202,918 | -$14.1M | +$39.5M |
| NEW | UNITEDHEALTH GROUP INC | UNH | +40,800 | +$13.5M | $0 |
| REDUCE | INSMED INC | INSM | -65,750 | -$11.4M | +$11.6M |
| REDUCE | CIDARA THERAPEUTICS INC | 171757206 | -44,524 | -$9.8M | +$31.2M |
| EXITED | MEREO BIOPHARMA GROUP PLC | 589492107 | -4,570,649 | -$9.4M | $0 |
| ADD | SPDR SERIES TRUST | 78464A870 | +70,250 | +$8.6M | +$3.3M |
Sector Allocation
Filing History
- 13F HOLDINGS REPORTQ/E Dec 202599 pos · $1.95B
- 13F HOLDINGS REPORTQ/E Sep 202593 pos · $1.71B
- 13F HOLDINGS REPORTQ/E Jun 202593 pos · $1.60B
- 13F HOLDINGS REPORTQ/E Mar 202596 pos · $1.75B
- 13F HOLDINGS REPORTQ/E Dec 2024107 pos · $2.63B
- 13F HOLDINGS REPORTQ/E Sep 2024109 pos · $3.07B
- 13F HOLDINGS REPORTQ/E Jun 2024112 pos · $3.32B
- 13F HOLDINGS REPORTQ/E Mar 2024114 pos · $3.94B
- 13F HOLDINGS REPORTQ/E Dec 2023120 pos · $3.73B
Top 20 Holdings — Dec 2025
| # | Issuer | Ticker | Shares | Value | % of Portfolio |
|---|---|---|---|---|---|
| 1 | ELI LILLY & CO | LLY | 105,400 | $113.3M | 6.57% |
| 2 | REVOLUTION MEDICINES INC | RVMDW | 1,335,270 | $106.4M | 6.17% |
| 3 | ARGENX SE | ARGX | 103,250 | $86.8M | 5.04% |
| 4 | TRAVERE THERAPEUTICS INC | TVTX | 2,210,322 | $84.5M | 4.90% |
| 5 | MADRIGAL PHARMACEUTICALS INC | MDGL | 139,618 | $81.3M | 4.72% |
| 6 | RHYTHM PHARMACEUTICALS INC | RYTM | 695,010 | $74.4M | 4.32% |
| 7 | EXACT SCIENCES CORP | 30063P105 | 601,800 | $61.1M | 3.55% |
| 8 | MIRUM PHARMACEUTICALS INC | MIRM | 762,294 | $60.2M | 3.49% |
| 9 | INSMED INC | INSM | 319,250 | $55.6M | 3.22% |
| 10 | STRUCTURE THERAPEUTICS INC | GPCR | 748,236 | $52.0M | 3.02% |
| 11 | INTUITIVE SURGICAL INC | ISRG | 82,000 | $46.4M | 2.70% |
| 12 | CIDARA THERAPEUTICS INC | 171757206 | 204,878 | $45.3M | 2.63% |
| 13 | ASCENDIS PHARMA A/S | ASND | 203,500 | $43.4M | 2.52% |
| 14 | IRHYTHM TECHNOLOGIES INC | IRTC | 235,000 | $41.7M | 2.42% |
| 15 | KYMERA THERAPEUTICS INC | KYMR | 496,871 | $38.7M | 2.24% |
| 16 | BOSTON SCIENTIFIC CORP | BSX | 399,050 | $38.0M | 2.21% |
| 17 | PENUMBRA INC | PEN | 120,500 | $37.5M | 2.17% |
| 18 | XENON PHARMACEUTICALS INC | XENE | 787,788 | $35.3M | 2.05% |
| 19 | SCHOLAR ROCK HLDG CORP | SRRK | 733,477 | $32.3M | 1.88% |
| 20 | COGENT BIOSCIENCES INC | COGT | 849,030 | $30.2M | 1.75% |