Q2 2026 13F · SEC CIK 1306923

Palo Alto Investors LP

Hedge fundFiled 2026-08-19 for Q2 2026. Open the filing ↗ · All SEC filings ↗

Reported 13F value: $723.7M
Reported positions: 52
Top holdings a year, 3 yrs: +10.6%
Assets under management: $696.0M

Palo Alto Investors LP is a hedge fund that reported 52 positions worth $723.7M in its Q2 2026 13F, filed 2026-08-19. Its largest holdings were Ptc Therapeutics Inc (PTCT, 10.4%), Acadia Pharmaceuticals Inc (ACAD, 10.0%), Insmed Inc (INSM, 6.1%). A portfolio copying its top holdings returned 10.6% a year over the last 3 years, against 20.4% for the S&P 500.

Palo Alto Investors LP holdings largest 50 of 52 positions.

Weights are shares of the filer's total reported 13F value, compared with Q1 2026. Share changes may reflect splits; weight changes also reflect price moves. A 13F shows long US-listed positions only, up to 135 days after the fact.

Palo Alto Investors LP 13F holdings
Stock	% of 13F value	Q1 2026	Shares	Share change	Reported value
PTCTPtc Therapeutics Inc	10.4%	9.6%	918,846	-0.3%	$75.0M
ACADAcadia Pharmaceuticals Inc	10.0%	9.8%	2,864,096	-0.3%	$72.5M
INSMInsmed Inc	6.1%	10.4%	413,980	-0.3%	$44.1M
MIRMMirum Pharmaceuticals Inc	5.6%	4.6%	348,808	+7.3%	$40.8M
ANABAnaptysbio Inc	5.6%	5.4%	603,489	-5.4%	$40.7M
BMRNBiomarin Pharmaceutical Inc	5.4%	5.9%	682,777	-0.4%	$39.1M
DYNDyne Therapeutics Inc	5.1%	4.6%	1,647,521	-0.3%	$36.6M
UTHRUnited Therapeutics Corp Del	4.7%	5.7%	62,587	-0.4%	$33.9M
IRONDisc Medicine Inc	4.2%	3.9%	416,646	+3.7%	$30.5M
BIIBBiogen Inc	4.2%	3.9%	140,279	-0.3%	$30.3M
IOVAIovance Biotherapeutics Inc	3.0%	3.4%	5,296,209	-16.6%	$22.0M
RAREUltragenyx Pharmaceutical in	2.8%	1.9%	596,495	+0.0%	$19.9M
NVCRNovocure Ltd	2.7%	2.1%	1,280,439	+0.0%	$19.4M
SNDXSyndax Pharmaceuticals Inc	2.6%	3.1%	864,986	+0.0%	$18.9M
ANNXAnnexon Inc	2.3%	2.5%	2,948,090	+0.0%	$16.8M
BCAXBicara Therapeutics Inc	2.3%	1.7%	550,408	+0.0%	$16.3M
CDNACareDx, Inc.	2.1%	1.4%	531,870	+0.0%	$15.2M
CLDXCelldex Therapeutics Inc New	2.1%	1.4%	399,856	+34.9%	$14.9M
CMPXCompass Therapeutics Inc	1.8%	1.2%	5,831,813	+285.1%	$12.8M
ALKSAlkermes PLC	1.8%	1.3%	242,560	+0.0%	$12.7M
TRAXFirst Tracks Biotherapeutics	1.7%	—	603,489	—	$12.1M
PRTAProthena Corp PLC Shs	1.5%	1.8%	1,143,155	-5.4%	$11.2M
TVTXTravere Therapeutics Inc	1.3%	1.0%	167,525	-27.3%	$9.5M
TSHATaysha Gene Therapies Inc	1.3%	1.0%	1,391,382	+0.0%	$9.5M
ACRSAclaris Therapeutics Inc	1.2%	0.9%	1,613,430	+0.0%	$8.5M
AGIOAgios Pharmaceuticals Inc	1.1%	1.1%	213,601	+0.0%	$7.9M
CAPRCapricor Therapeutics Inc	0.8%	1.1%	229,763	+0.0%	$5.5M
ALGNAlign Technology Inc	0.7%	1.1%	31,389	-24.4%	$5.3M
ORKAOruka Therapeutics Inc	0.4%	0.5%	33,546	-44.1%	$3.2M
XENEXenon Pharmaceuticals Inc	0.4%	0.5%	51,345	+0.0%	$3.1M
NBIXNeurocrine Biosciences Inc	0.4%	0.4%	18,117	+0.0%	$3.1M
EWEdwards Lifesciences Corp	0.4%	0.4%	33,640	+0.0%	$3.0M
STOKStoke Therapeutics Inc	0.4%	0.4%	84,631	+0.0%	$2.8M
CYTKCytokinetics	0.4%	0.3%	32,195	+0.0%	$2.7M
PYXSPyxis Oncology Inc	0.4%	0.2%	864,277	-14.5%	$2.6M
EHTHEhealth Inc	0.3%	0.3%	1,482,797	+0.0%	$2.2M
CRSPCrispr Therapeutics AG	0.3%	0.3%	39,605	+0.0%	$2.2M
SGMTSagimet Biosciences Inc	0.3%	—	250,000	—	$1.9M
NUVBNuvation Bio Inc	0.3%	0.3%	326,609	-35.8%	$1.9M
BNTXBiontech SE	0.3%	0.3%	19,614	+0.0%	$1.8M
CMPSCompass Pathways PLC	0.2%	0.1%	115,616	+0.0%	$1.6M
HUMHumana Inc	0.2%	0.1%	3,985	+0.0%	$1.6M
NAMSNewamsterdam Pharma Company Ordinary	0.2%	—	44,359	—	$1.5M
VSTMVerastem Inc	0.2%	0.2%	309,685	+25.8%	$1.2M
MDGLMadrigal Pharmaceuticals Inc	0.1%	0.1%	1,787	+0.0%	$960K
URGNUrogen Pharma Ltd	0.1%	0.1%	24,500	+0.0%	$902K
BCYCBicycle Therapeutics PLC	0.1%	0.1%	201,890	+0.0%	$856K
XERSXeris Biopharma Holdings Inc	0.1%	0.1%	104,410	+0.0%	$827K
ABEOAbeona Therapeutics	0.1%	0.1%	108,865	+0.0%	$673K
INSPInspire Med Sys Inc	0.1%	0.1%	8,772	+0.0%	$391K

What Palo Alto Investors LP bought and sold in Q2 2026, against Q1 2026.

New positions

Q1 2026's filing was too long to tell new positions apart.

Share counts compared with the Q1 2026 13F; a split also changes share counts. The latest filing lists more than 50 positions, so a position that left the top 50 may still be held.

How the holdings did against the S&P 500.

1 year: +46.4% /yr; S&P 500 +20.1%
3 years: +10.6% /yr; S&P 500 +20.4%
5 years: +4.0% /yr; S&P 500 +11.6%

A portfolio of the filer's 20 largest 13F positions, weighted by value, bought the trading day after each 13F was filed and held until the next one was: what copying this filer could have earned. 13Fs show long US-listed positions only, so this is an estimate of the stock picks, not the fund's reported returns.

Reported 13F value by quarter.

13F value by quarter
Quarter	13F value	Positions
Q2 2026	$723.7M	52
Q1 2026	$653.9M	51
Q4 2025	$718.4M	49
Q3 2025	$540.4M	44
Q2 2025	$470.0M	45
Q1 2025	$525.1M	44
Q4 2024	$645.4M	43
Q3 2024	$769.9M	45
Q2 2024	$863.0M	39
Q1 2024	$886.7M	38
Q4 2023	$1.1B	34
Q3 2023	$1.1B	29

Questions about Palo Alto Investors LP's portfolio

What stocks does Palo Alto Investors LP own?

Palo Alto Investors LP's latest 13F, for Q2 2026 and filed Aug 19, 2026, lists 52 positions worth $723.7M. The largest are Ptc Therapeutics Inc (PTCT) at 10.4%, Acadia Pharmaceuticals Inc (ACAD) at 10.0%, Insmed Inc (INSM) at 6.1%, Mirum Pharmaceuticals Inc (MIRM) at 5.6% and Anaptysbio Inc (ANAB) at 5.6%.

What did Palo Alto Investors LP buy last quarter?

In Q2 2026, Palo Alto Investors LP added Compass Therapeutics Inc (CMPX) (+285.1% shares), Celldex Therapeutics Inc New (CLDX) (+34.9% shares) and Verastem Inc (VSTM) (+25.8% shares), compared with its Q1 2026 filing.

What did Palo Alto Investors LP sell last quarter?

In Q2 2026, Palo Alto Investors LP cut from its top 50 Amicus Therapeutic (FOLD), cut from its top 50 Denali Therapeutics Inc Com (DNLI), cut from its top 50 Proqr Thrapeutics N V (PRQR), Oruka Therapeutics Inc (ORKA) (-44.1% shares), Nuvation Bio Inc (NUVB) (-35.8% shares) and Travere Therapeutics Inc (TVTX) (-27.3% shares), compared with its Q1 2026 filing.

How has Palo Alto Investors LP's portfolio performed?

A portfolio copying Palo Alto Investors LP's 20 largest 13F holdings each quarter, from the day each filing was public, returned +10.6% a year over the last 3 years, against +20.4% for the S&P 500. Over 1 year: +46.4% against +20.1%. Over 5 years: +4.0% a year against +11.6%.

When is Palo Alto Investors LP's next 13F filing due?

13F filings are due 45 days after each quarter ends. Palo Alto Investors LP's filing for the quarter ending Sep 30, 2026 is due by Nov 14, 2026; this page updates the day after it is published.

How much money does Palo Alto Investors LP manage?

Palo Alto Investors LP reported $696.0M of regulatory assets under management on its latest SEC Form ADV. Its 13F, which covers only US-listed stocks and options, totals $723.7M.