Latest Rock Springs Capital Management LP Stock Portfolio
Rock Springs Capital Management LP Performance:
2025 Q3: 17.66%YTD: 15.48%2024: -4.87%
Performance for 2025 Q3 is 17.66%, and YTD is 15.48%, and 2024 is -4.87%.
About Rock Springs Capital Management LP and 13F Hedge Fund Stock Holdings
Rock Springs Capital Management LP is a hedge fund based in BALTIMORE, MD. On 31-Mar-2023, the fund reported that it had an AUM (Regulated Assets under Management) of $5.7 Billions. In it's latest 13F Holdings report, Rock Springs Capital Management LP reported an equity portfolio of $1.7 Billions as of 30 Sep, 2025.
The top stock holdings of Rock Springs Capital Management LP are , LLY, RYTM. The fund has invested 6.2% of it's portfolio in ARGENX SE and 4.7% of portfolio in ELI LILLY & CO.
The fund managers got completely rid off BLUEPRINT MEDICINES CORP (BPMC), UNITEDHEALTH GROUP INC (UNH) and OSCAR HEALTH INC (OSCR) stocks. They significantly reduced their stock positions in COMPUGEN LTD, PROTHENA CORP PLC (PRTA) and WEST PHARMACEUTICAL SVSC INC (WST). Rock Springs Capital Management LP opened new stock positions in HEARTFLOW INC, BRIDGEBIO PHARMA INC (BBIO) and OCULAR THERAPEUTIX INC (OCUL). The fund showed a lot of confidence in some stocks as they added substantially to TALPHERA INC (ACRX), LENZ THERAPEUTICS INC and JASPER THERAPEUTICS INC (JSPR).
The top stock holdings of Rock Springs Capital Management LP are , LLY, RYTM. The fund has invested 6.2% of it's portfolio in ARGENX SE and 4.7% of portfolio in ELI LILLY & CO.
The fund managers got completely rid off BLUEPRINT MEDICINES CORP (BPMC), UNITEDHEALTH GROUP INC (UNH) and OSCAR HEALTH INC (OSCR) stocks. They significantly reduced their stock positions in COMPUGEN LTD, PROTHENA CORP PLC (PRTA) and WEST PHARMACEUTICAL SVSC INC (WST). Rock Springs Capital Management LP opened new stock positions in HEARTFLOW INC, BRIDGEBIO PHARMA INC (BBIO) and OCULAR THERAPEUTIX INC (OCUL). The fund showed a lot of confidence in some stocks as they added substantially to TALPHERA INC (ACRX), LENZ THERAPEUTICS INC and JASPER THERAPEUTICS INC (JSPR).
Rock Springs Capital Management LP Annual Return Estimates Vs S&P 500
Our best estimate is that Rock Springs Capital Management LP made a return of 17.66% in the last quarter. In trailing 12 months, it's portfolio return was 9.42%.
New Buys
| Ticker | $ Bought |
|---|---|
| heartflow inc | 8,415,000 |
| mbx biosciences inc | 4,945,920 |
| bridgebio pharma inc | 4,414,900 |
| ocular therapeutix inc | 3,507,000 |
| alkermes plc | 3,196,110 |
| centessa pharmaceuticals plc | 1,679,070 |
| mersana therapeutics inc | 1,184,070 |
| eyepoint pharmaceuticals inc | 450,767 |
New stocks bought by Rock Springs Capital Management LP
Additions
| Ticker | % Inc. |
|---|---|
| talphera inc | 1,034 |
| lenz therapeutics inc | 181 |
| jasper therapeutics inc | 101 |
| cidara therapeutics inc | 85.94 |
| dyne therapeutics inc | 41.84 |
| cogent biosciences inc | 26.01 |
| mineralys therapeutics inc | 25.82 |
| travere therapeutics inc | 13.45 |
Additions to existing portfolio by Rock Springs Capital Management LP
Reductions
| Ticker | % Reduced |
|---|---|
| compugen ltd | -98.64 |
| prothena corp plc | -94.84 |
| west pharmaceutical svsc inc | -80.89 |
| acadia healthcare company in | -75.57 |
| immunovant inc | -67.06 |
| merus n v | -43.87 |
| edwards lifesciences corp | -32.82 |
| insmed inc | -26.67 |
Rock Springs Capital Management LP reduced stake in above stock
Sold off
| Ticker | $ Sold |
|---|---|
| adaptimmune therapeutics plc | -595,287 |
| oscar health inc | -15,008,000 |
| cullinan therapeutics inc | -5,031,790 |
| pulmonx corp | -1,686,350 |
| blueprint medicines corp | -23,777,400 |
| mersana therapeutics inc | -1,129,150 |
| nuvalent inc | -7,120,930 |
| sarepta therapeutics inc | -1,173,060 |
Rock Springs Capital Management LP got rid off the above stocks
Sector Distribution
Rock Springs Capital Management LP has about 80.4% of it's holdings in Healthcare sector.
| Sector | % |
|---|---|
| Healthcare | 80.4 |
| Others | 19.6 |
Market Cap. Distribution
Rock Springs Capital Management LP has about 23.1% of it's portfolio invested in the large-cap and mega-cap stocks.
| Category | % |
|---|---|
| MID-CAP | 36.1 |
| UNALLOCATED | 21.1 |
| LARGE-CAP | 18.1 |
| SMALL-CAP | 15.6 |
| MEGA-CAP | 5 |
| MICRO-CAP | 4 |
Stocks belong to which Index?
About 56.6% of the stocks held by Rock Springs Capital Management LP either belong to S&P 500 or RUSSELL 2000 index.
| Index | % |
|---|---|
| RUSSELL 2000 | 44.5 |
| Others | 43.3 |
| S&P 500 | 12.1 |
Rock Springs Capital Management LP Holdings Map
This heatmap illustrates the top 50 positions within the fund's portfolio.
Current Stock Holdings of Rock Springs Capital Management LP
Rock Springs Capital Management LP has 91 stocks in it's portfolio. About 37.7% of the portfolio is in top 10 stocks. AGL proved to be the most loss making stock for the portfolio. MRUS was the most profitable stock for Rock Springs Capital Management LP last quarter.
Last Reported on: 14 Nov, 2025| Ticker | Namesorted ascending | % Portfolio | Shares Held | $ Value | Type | % Change | Options | |
|---|---|---|---|---|---|---|---|---|
| ACHC | acadia healthcare company in | 0.25 | 170,000 | 4,209,200 | reduced | -75.57 | ||
| ACLX | arcellx inc | 0.86 | 178,982 | 14,694,400 | reduced | -3.94 | ||
| ACRS | aclaris therapeutics inc | 0.51 | 4,609,310 | 8,757,690 | reduced | -3.35 | ||
| ACRX | talphera inc | 0.19 | 3,589,190 | 3,205,860 | added | 1,034 | ||
| ADAP | adaptimmune therapeutics plc | 0.00 | 0.00 | 0.00 | sold off | -100 | ||
| AGIO | agios pharmaceuticals inc | 2.25 | 958,542 | 38,475,900 | reduced | -3.15 | ||
| AGL | agilon health inc | 0.42 | 6,966,300 | 7,175,290 | added | 6.35 | ||
| AKRO | akero therapeutics inc | 1.74 | 626,526 | 29,747,500 | reduced | -2.19 | ||
| ALKS | alkermes plc | 0.19 | 106,537 | 3,196,110 | new | |||
| ALNY | alnylam pharmaceuticals inc | 1.98 | 74,250 | 33,858,000 | reduced | -25.75 | ||
| AMLX | amylyx pharmaceuticals inc | 0.40 | 499,764 | 6,791,790 | unchanged | 0.00 | ||
| APLS | apellis pharmaceuticals inc | 0.12 | 92,000 | 2,081,960 | added | 9.13 | ||
| APLT | applied therapeutics inc | 0.07 | 2,075,990 | 1,255,770 | unchanged | 0.00 | ||
| ARDX | ardelyx inc | 0.74 | 2,286,270 | 12,597,400 | unchanged | 0.00 | ||
| ATEC | alphatec hldgs inc | 0.26 | 302,500 | 4,398,350 | added | 13.08 | ||
| AZTA | azenta inc | 0.91 | 540,400 | 15,520,300 | added | 1.89 | ||
| BBIO | bridgebio pharma inc | 0.26 | 85,000 | 4,414,900 | new | |||
| BIL | spdr series trust | 0.89 | 151,750 | 15,205,400 | unchanged | 0.00 | ||
| BPMC | blueprint medicines corp | 0.00 | 0.00 | 0.00 | sold off | -100 | ||
| BSX | boston scientific corp | 2.06 | 360,250 | 35,171,200 | added | 1.48 | ||