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Palo Alto Investors LP

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13F filer, CIK 1306923, PALO ALTO, CA

Palo Alto Investors LP reported $525,145,307 across 44 holdings for the quarter ended 2025-03-31, in a 13F-HR filed 2025-05-15. Its ten largest share positions make up 74.78% of the portfolio.

Filed (acceptance time not in the bulk data set), ingested 13F-HR 0001306923-25-000014

Period
2025-03-31
Reported value
$525M
Holdings
44
Top 10 weight
74.78%
New
3
Sold out
2

Largest buys vs the previous quarter

SecurityShares changeApprox. value
AGIOnew+276,578$8.1M
DYNnew+333,391$3.49M
NVCRadded+187,870$3.35M
ANABadded+176,742$3.29M
BIIBadded+14,775$2.02M

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-616,312-$47M
KARYOPHARM THERAPEUTICS INCreduced-4,582,969-$17.1M
UTHRreduced-50,486-$15.6M
ALNYreduced-57,193-$15.4M
BMRNreduced-76,059-$5.38M

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, Q1 2025

Share positions as resolved from 13F-HR 0001306923-25-000014, largest first. % of portfolio is the value over $525,145,308, 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; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,940,993 shares; 2024Q4: 1,603,465 shares; 2025Q1: 987,153 shares 987,153$75.3M14.34%-616,312Timeline
BMRNBIOMARIN PHARMACEUTICAL INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,090,056 shares; 2024Q4: 1,067,266 shares; 2025Q1: 991,207 shares 991,207$70.1M13.34%-76,059Timeline
FOLDAMICUS THERAPEUTICQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 8,145,311 shares; 2024Q4: 7,662,479 shares; 2025Q1: 7,345,002 shares 7,345,002$59.9M11.41%-317,477Timeline
ACADACADIA PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 2,523,956 shares; 2024Q4: 2,748,599 shares; 2025Q1: 2,663,925 shares 2,663,925$44.2M8.43%-84,674Timeline
UTHRUNITED THERAPEUTICS CORP DELQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 183,246 shares; 2024Q4: 155,714 shares; 2025Q1: 105,228 shares 105,228$32.4M6.18%-50,486Timeline
BIIBBIOGEN INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 228,916 shares; 2024Q4: 190,148 shares; 2025Q1: 204,923 shares 204,923$28M5.34%+14,775Timeline
ALNYALNYLAM PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 140,681 shares; 2024Q4: 140,681 shares; 2025Q1: 83,488 shares 83,488$22.5M4.29%-57,193Timeline
PTCTPTC THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 264,469 shares; 2024Q4: 386,413 shares; 2025Q1: 404,196 shares 404,196$20.6M3.92%+17,783Timeline
PRTAPROTHENA CORP PLCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,737,964 shares; 2024Q4: 1,737,964 shares; 2025Q1: 1,659,734 shares 1,659,734$20.5M3.91%-78,230Timeline
ANABANAPTYSBIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 843,971 shares; 2024Q4: 843,971 shares; 2025Q1: 1,020,713 shares 1,020,713$19M3.61%+176,742Timeline
NVCRNOVOCURE LTDQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 593,540 shares; 2024Q4: 814,191 shares; 2025Q1: 1,002,061 shares 1,002,061$17.9M3.4%+187,870Timeline
SRPTSAREPTA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 210,258 shares; 2024Q4: 210,258 shares; 2025Q1: 210,258 shares 210,258$13.4M2.56%0Timeline
EHTHEHEALTH INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 2,347,519 shares; 2024Q4: 1,878,127 shares; 2025Q1: 1,684,336 shares 1,684,336$11.3M2.14%-193,791Timeline
IOVAIOVANCE BIOTHERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 3,041,685 shares; 2024Q4: 3,041,685 shares; 2025Q1: 3,211,314 shares 3,211,314$10.7M2.04%+169,629Timeline
STAASTAAR SURGICAL COQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,091,608 shares; 2024Q4: 500,775 shares; 2025Q1: 525,017 shares 525,017$9.26M1.76%+24,242Timeline
AGIOAGIOS PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: 276,578 shares 276,578$8.1M1.54%newTimeline
ALKSALKERMES PLCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 384,656 shares; 2024Q4: 289,308 shares; 2025Q1: 221,513 shares 221,513$7.31M1.39%-67,795Timeline
GOSSGOSSAMER BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 6,277,093 shares; 2024Q4: 6,277,093 shares; 2025Q1: 6,276,893 shares 6,276,893$6.9M1.31%-200Timeline
ALGNALIGN TECHNOLOGY INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 37,772 shares; 2024Q4: 37,772 shares; 2025Q1: 37,772 shares 37,772$6M1.14%0Timeline
SNDXSYNDAX PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 405,193 shares; 2024Q4: 405,193 shares; 2025Q1: 444,367 shares 444,367$5.46M1.04%+39,174Timeline
ACELYRIN INCACELYRIN INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 1,792,895 shares; 2024Q4: 1,792,895 shares; 2025Q1: 1,792,895 shares 1,792,895$4.43M0.84%0
DYNDYNE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: 333,391 shares 333,391$3.49M0.66%newTimeline
MIRMMIRUM PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 64,700 shares; 2024Q4: 64,700 shares; 2025Q1: 64,700 shares 64,700$2.91M0.56%0Timeline
EWEDWARDS LIFESCIENCES CORPQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 39,473 shares; 2024Q4: 39,473 shares; 2025Q1: 39,473 shares 39,473$2.86M0.54%0Timeline
VERVE THERAPEUTICS INCVERVE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 575,817 shares; 2024Q4: 575,817 shares; 2025Q1: 575,817 shares 575,817$2.63M0.5%0
BNTXBIONTECH SEQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 25,206 shares; 2024Q4: 25,206 shares; 2025Q1: 25,206 shares 25,206$2.3M0.44%0Timeline
BCYCBICYCLE THERAPEUTICS PLCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 59,582 shares; 2024Q4: 248,934 shares; 2025Q1: 248,934 shares 248,934$2.11M0.4%0Timeline
TVTXTRAVERE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 110,719 shares; 2024Q4: 110,719 shares; 2025Q1: 110,719 shares 110,719$1.98M0.38%0Timeline
TSHATAYSHA GENE THERAPIES INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 811,268 shares; 2024Q4: 811,268 shares; 2025Q1: 1,419,468 shares 1,419,468$1.97M0.38%+608,200Timeline
NBIXNEUROCRINE BIOSCIENCES INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: 13,334 shares 13,334$1.47M0.28%newTimeline
NUVBNUVATION BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 772,652 shares; 2024Q4: 772,652 shares; 2025Q1: 772,652 shares 772,652$1.36M0.26%0Timeline
ALDXALDEYRA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 225,465 shares; 2024Q4: 225,465 shares; 2025Q1: 225,465 shares 225,465$1.3M0.25%0Timeline
KARYOPHARM THERAPEUTICS INCKARYOPHARM THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 5,102,193 shares; 2024Q4: 4,907,001 shares; 2025Q1: 324,032 shares 324,032$1.21M0.23%-4,582,969
ACRSACLARIS THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 569,832 shares; 2024Q4: 569,832 shares; 2025Q1: 776,028 shares 776,028$1.19M0.23%+206,196Timeline
HUMHUMANA INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 3,985 shares; 2024Q4: 3,985 shares; 2025Q1: 3,985 shares 3,985$1.05M0.2%0Timeline
PYXSPYXIS ONCOLOGY INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 170,000 shares; 2024Q4: 1,037,421 shares; 2025Q1: 1,037,421 shares 1,037,421$1.02M0.19%0Timeline
STOKSTOKE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 125,861 shares; 2024Q4: 125,861 shares; 2025Q1: 125,861 shares 125,861$837K0.16%0Timeline
VYNEVYNE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 445,434 shares; 2024Q4: 445,434 shares; 2025Q1: 445,434 shares 445,434$704K0.13%0Timeline
ABEOABEONA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 12,865 shares; 2024Q4: 108,865 shares; 2025Q1: 108,865 shares 108,865$518K0.1%0Timeline
URGNUROGEN PHARMA LTDQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 24,500 shares; 2024Q4: 24,500 shares; 2025Q1: 24,500 shares 24,500$271K0.05%0Timeline
TILINSTIL BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 11,165 shares; 2024Q4: 11,165 shares; 2025Q1: 11,165 shares 11,165$194K0.04%0Timeline
AKTXAKARI THERAPEUTICS PLC SPONSORQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: 146,024 shares; 2025Q1: 146,024 shares 146,024$181K0.03%0Timeline
RLMDRELMADA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 732,400 shares; 2024Q4: 495,146 shares; 2025Q1: 495,146 shares 495,146$134K0.03%0Timeline
GENERATION BIO COGENERATION BIO COQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2023Q2: restricted; 2023Q3: restricted; 2023Q4: restricted; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 150,475 shares; 2024Q4: 150,475 shares; 2025Q1: 150,475 shares 150,475$60.9K0.01%0

Sold out in Q1 2025

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

SecurityShares beforeValue beforeType
NEVRO CORPNEVRO CORP750,371$2.79Mshares
JSPRJASPER THERAPEUTICS INC30,651$655Kshares

How Q1 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 0001306923-25-000014 base2025-05-15acceptance time not in the bulk data set