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Palo Alto Investors LP

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13F filer, CIK 1306923, PALO ALTO, CA

Palo Alto Investors LP reported $540,390,359 across 44 holdings for the quarter ended 2025-09-30, in a 13F-HR filed 2025-11-14. Its ten largest share positions make up 67.23% of the portfolio.

Filed (acceptance time not in the bulk data set), ingested 13F-HR 0001306923-25-000019

Period
2025-09-30
Reported value
$540M
Holdings
44
Top 10 weight
67.23%
New
3
Sold out
4

Largest buys vs the previous quarter

SecurityShares changeApprox. value
PTCTadded+456,144$28M
DYNadded+997,698$12.6M
RAREadded+320,781$9.65M
IOVAadded+4,188,803$9.09M
IRONadded+78,609$5.19M

Ranked by the share change valued at this quarter's implied price (value over shares in the 13F). A position sold out is valued at the previous quarter's price, its last report.

Largest sells vs the previous quarter

SecurityShares changeApprox. value
INSMreduced-373,308-$53.8M
ALNYreduced-43,215-$19.7M
UTHRreduced-37,296-$15.6M
STAAexited-791,879-$13.3M
BMRNreduced-86,463-$4.68M

Ranked by the share change valued at this quarter's implied price (value over shares in the 13F). A position sold out is valued at the previous quarter's price, its last report.

Holdings, Q3 2025

Share positions as resolved from 13F-HR 0001306923-25-000019, largest first. % of portfolio is the value over $540,390,359, the sum of the share positions whose value is usable for ratios (method).

SecurityHistorySharesValue% of portfolioChangeLatest eventTimeline
INSMINSMED INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,940,993 shares; 2024Q4: 1,603,465 shares; 2025Q1: 987,153 shares; 2025Q2: 865,113 shares; 2025Q3: 491,805 shares 491,805$70.8M13.11%-373,308Timeline
PTCTPTC THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 264,469 shares; 2024Q4: 386,413 shares; 2025Q1: 404,196 shares; 2025Q2: 406,469 shares; 2025Q3: 862,613 shares 862,613$52.9M9.8%+456,144Timeline
ACADACADIA PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 2,523,956 shares; 2024Q4: 2,748,599 shares; 2025Q1: 2,663,925 shares; 2025Q2: 2,563,209 shares; 2025Q3: 2,466,684 shares 2,466,684$52.6M9.74%-96,525Timeline
FOLDAMICUS THERAPEUTICQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 8,145,311 shares; 2024Q4: 7,662,479 shares; 2025Q1: 7,345,002 shares; 2025Q2: 5,610,513 shares; 2025Q3: 5,367,798 shares 5,367,798$42.3M7.83%-242,715Timeline
BMRNBIOMARIN PHARMACEUTICAL INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,090,056 shares; 2024Q4: 1,067,266 shares; 2025Q1: 991,207 shares; 2025Q2: 840,470 shares; 2025Q3: 754,007 shares 754,007$40.8M7.56%-86,463Timeline
BIIBBIOGEN INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 228,916 shares; 2024Q4: 190,148 shares; 2025Q1: 204,923 shares; 2025Q2: 205,759 shares; 2025Q3: 185,661 shares 185,661$26M4.81%-20,098Timeline
UTHRUNITED THERAPEUTICS CORP DELQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 183,246 shares; 2024Q4: 155,714 shares; 2025Q1: 105,228 shares; 2025Q2: 95,482 shares; 2025Q3: 58,186 shares 58,186$24.4M4.51%-37,296Timeline
ANABANAPTYSBIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 843,971 shares; 2024Q4: 843,971 shares; 2025Q1: 1,020,713 shares; 2025Q2: 812,821 shares; 2025Q3: 673,520 shares 673,520$20.6M3.82%-139,301Timeline
IOVAIOVANCE BIOTHERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 3,041,685 shares; 2024Q4: 3,041,685 shares; 2025Q1: 3,211,314 shares; 2025Q2: 3,429,329 shares; 2025Q3: 7,618,132 shares 7,618,132$16.5M3.06%+4,188,803Timeline
NVCRNOVOCURE LTDQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 593,540 shares; 2024Q4: 814,191 shares; 2025Q1: 1,002,061 shares; 2025Q2: 962,396 shares; 2025Q3: 1,256,159 shares 1,256,159$16.2M3%+293,763Timeline
DYNDYNE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: 333,391 shares; 2025Q2: 264,976 shares; 2025Q3: 1,262,674 shares 1,262,674$16M2.96%+997,698Timeline
IRONDISC MEDICINE INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 145,691 shares; 2025Q3: 224,300 shares 224,300$14.8M2.74%+78,609Timeline
ALNYALNYLAM PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 140,681 shares; 2024Q4: 140,681 shares; 2025Q1: 83,488 shares; 2025Q2: 75,535 shares; 2025Q3: 32,320 shares 32,320$14.7M2.73%-43,215Timeline
GOSSGOSSAMER BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 6,277,093 shares; 2024Q4: 6,277,093 shares; 2025Q1: 6,276,893 shares; 2025Q2: 5,739,013 shares; 2025Q3: 5,464,349 shares 5,464,349$14.4M2.66%-274,664Timeline
PRTAPROTHENA CORP PLCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,737,964 shares; 2024Q4: 1,737,964 shares; 2025Q1: 1,659,734 shares; 2025Q2: 1,274,753 shares; 2025Q3: 1,324,028 shares 1,324,028$12.9M2.39%+49,275Timeline
RAREULTRAGENYX PHARMACEUTICAL INQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 48,750 shares; 2025Q3: 369,531 shares 369,531$11.1M2.06%+320,781Timeline
AGIOAGIOS PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: 276,578 shares; 2025Q2: 268,783 shares; 2025Q3: 265,497 shares 265,497$10.7M1.97%-3,286Timeline
SNDXSYNDAX PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 405,193 shares; 2024Q4: 405,193 shares; 2025Q1: 444,367 shares; 2025Q2: 444,367 shares; 2025Q3: 654,930 shares 654,930$10.1M1.86%+210,563Timeline
EHTHEHEALTH INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 2,347,519 shares; 2024Q4: 1,878,127 shares; 2025Q1: 1,684,336 shares; 2025Q2: 1,577,850 shares; 2025Q3: 1,544,619 shares 1,544,619$6.66M1.23%-33,231Timeline
DNLIDENALI THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 239,809 shares; 2025Q3: 408,006 shares 408,006$5.92M1.1%+168,197Timeline
ALGNALIGN TECHNOLOGY INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 37,772 shares; 2024Q4: 37,772 shares; 2025Q1: 37,772 shares; 2025Q2: 37,772 shares; 2025Q3: 45,735 shares 45,735$5.73M1.06%+7,963Timeline
ALKSALKERMES PLCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 384,656 shares; 2024Q4: 289,308 shares; 2025Q1: 221,513 shares; 2025Q2: 221,021 shares; 2025Q3: 183,938 shares 183,938$5.52M1.02%-37,083Timeline
RNAMAVIDITY BIOSCIENCES INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 118,886 shares; 2025Q3: 109,831 shares 109,831$4.79M0.89%-9,055Timeline
MIRMMIRUM PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 64,700 shares; 2024Q4: 64,700 shares; 2025Q1: 64,700 shares; 2025Q2: 64,700 shares; 2025Q3: 64,700 shares 64,700$4.74M0.88%0Timeline
CDNACAREDX INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: 316,204 shares 316,204$4.6M0.85%newTimeline
TSHATAYSHA GENE THERAPIES INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 811,268 shares; 2024Q4: 811,268 shares; 2025Q1: 1,419,468 shares; 2025Q2: 1,246,033 shares; 2025Q3: 1,246,033 shares 1,246,033$4.07M0.75%0Timeline
NUVBNUVATION BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 772,652 shares; 2024Q4: 772,652 shares; 2025Q1: 772,652 shares; 2025Q2: 772,652 shares; 2025Q3: 1,020,547 shares 1,020,547$3.78M0.7%+247,895Timeline
ACRSACLARIS THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 569,832 shares; 2024Q4: 569,832 shares; 2025Q1: 776,028 shares; 2025Q2: 1,390,028 shares; 2025Q3: 1,566,840 shares 1,566,840$2.98M0.55%+176,812Timeline
CRSPCRISPR THERAPEUTICS AGQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 44,625 shares; 2025Q3: 41,226 shares 41,226$2.67M0.49%-3,399Timeline
TVTXTRAVERE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 110,719 shares; 2024Q4: 110,719 shares; 2025Q1: 110,719 shares; 2025Q2: 110,719 shares; 2025Q3: 110,719 shares 110,719$2.65M0.49%0Timeline
EWEDWARDS LIFESCIENCES CORPQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 39,473 shares; 2024Q4: 39,473 shares; 2025Q1: 39,473 shares; 2025Q2: 39,473 shares; 2025Q3: 33,640 shares 33,640$2.62M0.48%-5,833Timeline
NBIXNEUROCRINE BIOSCIENCES INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: 13,334 shares; 2025Q2: 13,334 shares; 2025Q3: 18,117 shares 18,117$2.54M0.47%+4,783Timeline
STOKSTOKE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 125,861 shares; 2024Q4: 125,861 shares; 2025Q1: 125,861 shares; 2025Q2: 125,861 shares; 2025Q3: 105,427 shares 105,427$2.48M0.46%-20,434Timeline
PYXSPYXIS ONCOLOGY INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 170,000 shares; 2024Q4: 1,037,421 shares; 2025Q1: 1,037,421 shares; 2025Q2: 1,037,421 shares; 2025Q3: 1,037,421 shares 1,037,421$2.3M0.43%0Timeline
BNTXBIONTECH SEQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 25,206 shares; 2024Q4: 25,206 shares; 2025Q1: 25,206 shares; 2025Q2: 25,206 shares; 2025Q3: 19,614 shares 19,614$1.93M0.36%-5,592Timeline
BCYCBICYCLE THERAPEUTICS PLCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 59,582 shares; 2024Q4: 248,934 shares; 2025Q1: 248,934 shares; 2025Q2: 248,934 shares; 2025Q3: 221,071 shares 221,071$1.71M0.32%-27,863Timeline
ALDXALDEYRA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 225,465 shares; 2024Q4: 225,465 shares; 2025Q1: 225,465 shares; 2025Q2: 225,465 shares; 2025Q3: 225,465 shares 225,465$1.18M0.22%0Timeline
HUMHUMANA INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 3,985 shares; 2024Q4: 3,985 shares; 2025Q1: 3,985 shares; 2025Q2: 3,985 shares; 2025Q3: 3,985 shares 3,985$1.04M0.19%0Timeline
ORKAORUKA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: 59,985 shares 59,985$791K0.15%newTimeline
ABEOABEONA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 12,865 shares; 2024Q4: 108,865 shares; 2025Q1: 108,865 shares; 2025Q2: 108,865 shares; 2025Q3: 108,865 shares 108,865$575K0.11%0Timeline
URGNUROGEN PHARMA LTDQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 24,500 shares; 2024Q4: 24,500 shares; 2025Q1: 24,500 shares; 2025Q2: 24,500 shares; 2025Q3: 24,500 shares 24,500$489K0.09%0Timeline
PRQRPROQR THRAPEUTICS N VQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: 188,807 shares 188,807$402K0.07%newTimeline
AKTXAKARI THERAPEUTICS PLC SPONSORQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: 146,024 shares; 2025Q1: 146,024 shares; 2025Q2: 146,024 shares; 2025Q3: 146,024 shares 146,024$147K0.03%0Timeline
GENERATION BIO COGENERATION BIO COQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 150,475 shares; 2024Q4: 150,475 shares; 2025Q1: 150,475 shares; 2025Q2: 150,475 shares; 2025Q3: 15,047 shares 15,047$92.1K0.02%-135,428

Sold out in Q3 2025

Positions in the previous quarter's report that this quarter's report no longer lists.

SecurityShares beforeValue beforeType
STAASTAAR SURGICAL CO791,879$13.3Mshares
KPTIKARYOPHARM THERAPEUTICS INC187,911$810Kshares
VYNEVYNE THERAPEUTICS INC445,434$735Kshares
ALMSALUMIS INC143,437$430Kshares

How Q3 2025 was built

Available 13F filings of this filer for the quarter and their roles: the base report is the latest original or restatement, NEW HOLDINGS amendments filed after it are added (method).

FilingRoleAmendmentFiledAcceptedIngested
13F-HR 0001306923-25-000019 base2025-11-14acceptance time not in the bulk data set