Palo Alto Investors LP

In its 13F for Q2 2026 (holdings as of June 30, 2026, filed August 19, 2026), Palo Alto Investors LP reported 52 stock positions worth $723.7 million. Its top holding was PTC Therapeutics (PTCT) at 10.4% of the portfolio, followed by Acadia Pharmaceuticals (ACAD, 10.0%) and Insmed (INSM, 6.1%). Compared with Q1 2026, it opened 3 new positions, sold out of 2, added to 5 and reduced 15. The biggest buy was a new position in First Tracks Biotherapeutics (TRAX) and the biggest sale Insmed (INSM, shares −0%).

Most Recent 13F
Q2 2026
Location
PALO ALTO, CA
CIK
0001306923
Portfolio Value
$723.7M (Q2 2026)
SEC Filing
0002073679-26-000102 ↗ filed Aug 19, 2026

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 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 $723.7M Q2 2026

Holdings 52 stocks · $723.7M
PTCT PTC Therapeutics Inc. 10.36% 918,846 $75.0M Reduce -0.3%
ACAD Acadia Pharmaceuticals Inc. 10.01% 2,864,096 $72.5M Reduce -0.3%
INSM Insmed Inc. 6.10% 413,980 $44.1M Reduce -0.3%
MIRM Mirum Pharmaceuticals Inc. 5.64% 348,808 $40.8M Add +7.3%
ANAB Anaptysbio Inc. 5.63% 603,489 $40.7M Reduce -5.4%
BMRN Biomarin Pharmaceutical Inc. 5.40% 682,777 $39.1M Reduce -0.3%
DYN Dyne Therapeutics Inc. 5.06% 1,647,521 $36.6M Reduce -0.3%
UTHR United Therapeutics Corp. 4.69% 62,587 $33.9M Reduce -0.3%
IRON Disc Medicine Inc. 4.21% 416,646 $30.5M Add +3.7%
BIIB Biogen Inc. 4.19% 140,279 $30.3M Reduce -0.3%
IOVA Iovance Biotherapeutics Inc. 3.04% 5,296,209 $22.0M Reduce -16.6%
RARE Ultragenyx Pharmaceutical Inc. 2.75% 596,495 $19.9M No change
NVCR Novocure Ltd. 2.68% 1,280,439 $19.4M No change
SNDX Syndax Pharmaceuticals Inc. 2.61% 864,986 $18.9M No change
ANNX Annexon Inc. 2.33% 2,948,090 $16.8M No change
BCAX Bicara Therapeutics Inc. 2.26% 550,408 $16.3M No change
CDNA Caredx Inc. 2.09% 531,870 $15.2M No change
CLDX Celldex Therapeutics Inc. 2.06% 399,856 $14.9M Add +34.9%
CMPX Compass Therapeutics Inc. 1.76% 5,831,813 $12.8M Add +285.1%
ALKS Alkermes PLC 1.76% 242,560 $12.7M No change
TRAX First Tracks Biotherapeutics 1.68% 603,489 $12.1M New
PRTA Prothena Corp. PLC 1.55% 1,143,155 $11.2M Reduce -5.4%
TVTX Travere Therapeutics Inc. 1.31% 167,525 $9.5M Reduce -27.3%
TSHA Taysha Gene Therapies Inc. 1.31% 1,391,382 $9.5M No change
ACRS Aclaris Therapeutics Inc. 1.18% 1,613,430 $8.5M No change
AGIO Agios Pharmaceuticals Inc. 1.10% 213,601 $7.9M No change
CAPR Capricor Therapeutics Inc. 0.76% 229,763 $5.5M No change
ALGN Align Technology Inc. 0.73% 31,389 $5.3M Reduce -24.4%
ORKA Oruka Therapeutics Inc. 0.44% 33,546 $3.2M Reduce -44.1%
XENE Xenon Pharmaceuticals Inc. 0.43% 51,345 $3.1M No change
NBIX Neurocrine Biosciences Inc. 0.42% 18,117 $3.1M No change
EW Edwards Lifesciences Corp. 0.42% 33,640 $3.0M No change
STOK Stoke Therapeutics Inc. 0.38% 84,631 $2.8M No change
CYTK Cytokinetics Inc. 0.38% 32,195 $2.7M No change
PYXS Pyxis Oncology Inc. 0.36% 864,277 $2.6M Reduce -14.5%
EHTH Ehealth Inc. 0.31% 1,482,797 $2.2M No change
CRSP Crispr Therapeutics AG 0.30% 39,605 $2.2M No change
SGMT Sagimet Biosciences Inc. Class A 0.27% 250,000 $1.9M New
NUVB Nuvation Bio Inc. 0.26% 326,609 $1.9M Reduce -35.8%
BNTX Biontech SE-ADR 0.25% 19,614 $1.8M No change
CMPS Compass Pathways PLC 0.23% 115,616 $1.6M No change
HUM Humana Inc. 0.22% 3,985 $1.6M No change
NAMS Newamsterdam Pharma Co. NV 0.21% 44,359 $1.5M New
VSTM Verastem Inc. 0.16% 309,685 $1.2M Add +25.8%
MDGL Madrigal Pharmaceuticals Inc. 0.13% 1,787 $960K No change
URGN Urogen Pharma Ltd. 0.12% 24,500 $902K No change
BCYC Bicycle Therapeutics PLC-ADR 0.12% 201,890 $856K No change
XERS Xeris Biopharma Holdings Inc. 0.11% 104,410 $827K No change
ABEO Abeona Therapeutics Inc. 0.09% 108,865 $673K No change
INSP Inspire Medical Systems Inc. 0.05% 8,772 $391K No change
PRQR Proqr Therapeutics NV 0.05% 188,807 $351K No change
ALDX Aldeyra Therapeutics Inc. 0.05% 155,709 $332K No change

Portfolio Sells Q1 2026 → Q2 2026
INSM Insmed Inc. Reduce -0.3% 6.10% −4.29
FOLD Amicus Therapeutics Inc. Sold out 0.00% −2.46
UTHR United Therapeutics Corp. Reduce -0.3% 4.69% −1.01
DNLI Denali Therapeutics Inc. Sold out 0.00% −0.69
BMRN Biomarin Pharmaceutical Inc. Reduce -0.3% 5.40% −0.52
IOVA Iovance Biotherapeutics Inc. Reduce -16.6% 3.04% −0.36
ALGN Align Technology Inc. Reduce -24.4% 0.73% −0.36
PRTA Prothena Corp. PLC Reduce -5.4% 1.55% −0.25
NUVB Nuvation Bio Inc. Reduce -35.8% 0.26% −0.08
ORKA Oruka Therapeutics Inc. Reduce -44.1% 0.44% −0.01
PYXS Pyxis Oncology Inc. Reduce -14.5% 0.36% +0.13
ANAB Anaptysbio Inc. Reduce -5.4% 5.63% +0.22
ACAD Acadia Pharmaceuticals Inc. Reduce -0.3% 10.01% +0.23
BIIB Biogen Inc. Reduce -0.3% 4.19% +0.24
TVTX Travere Therapeutics Inc. Reduce -27.3% 1.31% +0.27
DYN Dyne Therapeutics Inc. Reduce -0.3% 5.06% +0.47
PTCT PTC Therapeutics Inc. Reduce -0.3% 10.36% +0.75

Portfolio Buys Q1 2026 → Q2 2026
TRAX First Tracks Biotherapeutics New 1.68% +1.68
MIRM Mirum Pharmaceuticals Inc. Add +7.3% 5.64% +1.05
CLDX Celldex Therapeutics Inc. Add +34.9% 2.06% +0.62
CMPX Compass Therapeutics Inc. Add +285.1% 1.76% +0.54
IRON Disc Medicine Inc. Add +3.7% 4.21% +0.28
SGMT Sagimet Biosciences Inc. Class A New 0.27% +0.27
NAMS Newamsterdam Pharma Co. NV New 0.21% +0.21
VSTM Verastem Inc. Add +25.8% 0.16% −0.04

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