Palo Alto Investors LP

In its 13F for Q4 2024 (holdings as of December 31, 2024, filed February 14, 2025), Palo Alto Investors LP reported 43 stock positions worth $645.4 million. Its top holding was Insmed (INSM) at 17.2% of the portfolio, followed by Amicus Therapeutics (FOLD, 11.2%) and Biomarin Pharmaceutical (BMRN, 10.9%). Compared with Q3 2024, it opened 2 new positions, sold out of 4, added to 6 and reduced 10. The biggest buy was Acadia Pharmaceuticals (ACAD, shares +9%) and the biggest sale Staar Surgical (STAA, shares −54%).

Most Recent 13F
Q2 2026
Location
PALO ALTO, CA
CIK
0001306923
Portfolio Value
$645.4M (Q4 2024)
SEC Filing
0001306923-25-000010 ↗ filed Feb 14, 2025

Holdings Value

0$200.0M$400.0M$600.0M$800.0M$1.0B Q1 2024: $886.7M Q1 2024 Q2 2024: $863.0M Q2 2024 Q3 2024: $769.9M Q3 2024 Q4 2024: $645.4M $645.4M Q4 2024 Q1 2025: $525.1M Q1 2025 Q2 2025: $470.0M Q2 2025 Q3 2025: $540.4M Q3 2025 Q4 2025: $718.4M Q4 2025 Q1 2026: $653.9M Q1 2026 Q2 2026: $723.7M Q2 2026

Holdings 43 stocks · $645.4M
INSM Insmed Inc. 17.15% 1,603,465 $110.7M Reduce -17.4%
FOLD Amicus Therapeutics Inc. 11.18% 7,662,479 $72.2M Reduce -5.9%
BMRN Biomarin Pharmaceutical Inc. 10.87% 1,067,266 $70.2M Reduce -2.1%
UTHR United Therapeutics Corp. 8.51% 155,714 $54.9M Reduce -15.0%
ACAD Acadia Pharmaceuticals Inc. 7.82% 2,748,599 $50.4M Add +8.9%
ALNY Alnylam Pharmaceuticals Inc. 5.13% 140,681 $33.1M No change
BIIB Biogen Inc. 4.51% 190,148 $29.1M Reduce -16.9%
SRPT Sarepta Therapeutics Inc. 3.96% 210,258 $25.6M No change
NVCR Novocure Ltd. 3.76% 814,191 $24.3M Add +37.2%
PRTA Prothena Corp. PLC 3.73% 1,737,964 $24.1M No change
IOVA Iovance Biotherapeutics Inc. 3.49% 3,041,685 $22.5M No change
EHTH Ehealth Inc. 2.74% 1,878,127 $17.7M Reduce -20.0%
PTCT PTC Therapeutics Inc. 2.70% 386,413 $17.4M Add +46.1%
STAA Staar Surgical Co. 1.88% 500,775 $12.2M Reduce -54.1%
ANAB Anaptysbio Inc. 1.73% 843,971 $11.2M No change
ALKS Alkermes PLC 1.29% 289,308 $8.3M Reduce -24.8%
ALGN Align Technology Inc. 1.22% 37,772 $7.9M No change
GOSS Gossamer Bio Inc. 0.88% 6,277,093 $5.7M No change
SLRN Acelyrin Inc. 0.87% 1,792,895 $5.6M No change
SNDX Syndax Pharmaceuticals Inc. 0.83% 405,193 $5.4M No change
BCYC Bicycle Therapeutics PLC-ADR 0.54% 248,934 $3.5M Add +317.8%
KPTI Karyopharm Therapeutics Inc. 0.51% 4,907,001 $3.3M Reduce -3.8%
VERV Verve Therapeutics Inc. 0.50% 575,817 $3.2M No change
EW Edwards Lifesciences Corp. 0.45% 39,473 $2.9M No change
BNTX Biontech SE-ADR 0.45% 25,206 $2.9M No change
NVRO Nevro LLC filed as NEVRO CORP 0.43% 750,371 $2.8M No change
MIRM Mirum Pharmaceuticals Inc. 0.41% 64,700 $2.7M No change
NUVB Nuvation Bio Inc. 0.32% 772,652 $2.1M No change
TVTX Travere Therapeutics Inc. 0.30% 110,719 $1.9M No change
PYXS Pyxis Oncology Inc. 0.25% 1,037,421 $1.6M Add +510.3%
VYNE THERAPEUTICS INC 0.23% 445,434 $1.5M No change
ACRS Aclaris Therapeutics Inc. 0.22% 569,832 $1.4M No change
TSHA Taysha Gene Therapies Inc. 0.22% 811,268 $1.4M No change
STOK Stoke Therapeutics Inc. 0.22% 125,861 $1.4M No change
ALDX Aldeyra Therapeutics Inc. 0.17% 225,465 $1.1M No change
HUM Humana Inc. 0.16% 3,985 $1.0M No change
JSPR Jasper Therapeutics Inc. 0.10% 30,651 $655K New
ABEO Abeona Therapeutics Inc. 0.09% 108,865 $606K Add +746.2%
URGN Urogen Pharma Ltd. 0.04% 24,500 $261K No change
RLMD Relmada Therapeutics Inc. 0.04% 495,146 $257K Reduce -32.4%
TIL Instil Bio Inc. 0.03% 11,165 $213K No change
AKTX Akari Therapeutics PLC 0.03% 146,024 $178K New
GBIO Generation Bio Co. 0.02% 150,475 $160K No change

Portfolio Sells Q3 2024 → Q4 2024
STAA Staar Surgical Co. Reduce -54.1% 1.88% −3.38
BIIB Biogen Inc. Reduce -16.9% 4.51% −1.26
INSM Insmed Inc. Reduce -17.4% 17.15% −1.25
RVNC Revance Therapeutics Inc. Sold out 0.00% −1.09
SAGE Sage Therapeutics Inc. Sold out 0.00% −0.95
RLMD Relmada Therapeutics Inc. Reduce -32.4% 0.04% −0.27
FOLD Amicus Therapeutics Inc. Reduce -5.9% 11.18% −0.12
ALKS Alkermes PLC Reduce -24.8% 1.29% −0.11
ELEV Elevation Oncology Inc. Sold out 0.00% −0.10
BLUEBIRD BIO INC Sold out 0.00% −0.04
KPTI Karyopharm Therapeutics Inc. Reduce -3.8% 0.51% −0.04
UTHR United Therapeutics Corp. Reduce -15.0% 8.51% −0.02
BMRN Biomarin Pharmaceutical Inc. Reduce -2.1% 10.87% +0.92
EHTH Ehealth Inc. Reduce -20.0% 2.74% +1.49

Portfolio Buys Q3 2024 → Q4 2024
ACAD Acadia Pharmaceuticals Inc. Add +8.9% 7.82% +2.77
NVCR Novocure Ltd. Add +37.2% 3.76% +2.55
PTCT PTC Therapeutics Inc. Add +46.1% 2.70% +1.43
BCYC Bicycle Therapeutics PLC-ADR Add +317.8% 0.54% +0.36
PYXS Pyxis Oncology Inc. Add +510.3% 0.25% +0.17
JSPR Jasper Therapeutics Inc. New 0.10% +0.10
ABEO Abeona Therapeutics Inc. Add +746.2% 0.09% +0.08
AKTX Akari Therapeutics PLC New 0.03% +0.03

All Filings

QuarterPositions13F Reported ValueTop Holdings
Q2 2026Amended 52$723.7MPTCT, ACAD, INSM, MIRM, ANAB
Q1 2026 51$653.9MINSM, ACAD, PTCT, BMRN, UTHR
Q4 2025 49$718.4MINSM, FOLD, PTCT, ACAD, BMRN
Q3 2025 44$540.4MINSM, PTCT, ACAD, FOLD, BMRN
Q2 2025 45$470.0MINSM, ACAD, BMRN, FOLD, UTHR
Q1 2025 44$525.1MINSM, BMRN, FOLD, ACAD, UTHR
Q4 2024 43$645.4MINSM, FOLD, BMRN, UTHR, ACAD
Q3 2024 45$769.9MINSM, FOLD, BMRN, UTHR, BIIB
Q2 2024 39$863.0MINSM, BMRN, FOLD, UTHR, BIIB
Q1 2024 38$886.7MINSM, FOLD, BMRN, BIIB, UTHR