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Palo Alto Investors LP

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13F filer, CIK 1306923, PALO ALTO, CA

Palo Alto Investors LP reported $718,352,025 across 49 holdings for the quarter ended 2025-12-31, in a 13F-HR filed 2026-02-17. Its ten largest share positions make up 67.77% of the portfolio.

Filed (acceptance time not in the bulk data set), ingested 13F-HR 0001306923-26-000002

Period
2025-12-31
Reported value
$718M
Holdings
49
Top 10 weight
67.77%
New
8
Sold out
3

Largest buys vs the previous quarter

SecurityShares changeApprox. value
CMPXnew+2,532,419$13.6M
ANNXnew+2,384,192$12M
IRONadded+93,156$7.4M
MIRMadded+91,721$7.25M
CAPRnew+226,304$6.53M

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
ALNYexited-32,320-$14.7M
RNAMexited-109,831-$4.79M
NUVBreduced-482,468-$4.32M
GOSSreduced-992,757-$3.08M
FOLDreduced-162,031-$2.31M

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, Q4 2025

Share positions as resolved from 13F-HR 0001306923-26-000002, largest first. % of portfolio is the value over $718,352,025, 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; 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; 2025Q4: 489,482 shares 489,482$85.2M11.86%-2,323Timeline
FOLDAMICUS THERAPEUTICQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2025Q4: 5,205,767 shares 5,205,767$74.1M10.32%-162,031Timeline
PTCTPTC THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 264,469 shares; 2024Q4: 386,413 shares; 2025Q1: 404,196 shares; 2025Q2: 406,469 shares; 2025Q3: 862,613 shares; 2025Q4: 903,916 shares 903,916$68.7M9.56%+41,303Timeline
ACADACADIA PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2025Q4: 2,484,031 shares 2,484,031$66.3M9.24%+17,347Timeline
BMRNBIOMARIN PHARMACEUTICAL INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2025Q4: 746,256 shares 746,256$44.3M6.17%-7,751Timeline
ANABANAPTYSBIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2025Q4: 690,032 shares 690,032$33.5M4.66%+16,512Timeline
BIIBBIOGEN INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 228,916 shares; 2024Q4: 190,148 shares; 2025Q1: 204,923 shares; 2025Q2: 205,759 shares; 2025Q3: 185,661 shares; 2025Q4: 183,571 shares 183,571$32.3M4.5%-2,090Timeline
DYNDYNE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: 333,391 shares; 2025Q2: 264,976 shares; 2025Q3: 1,262,674 shares; 2025Q4: 1,472,197 shares 1,472,197$28.8M4.01%+209,523Timeline
UTHRUNITED THERAPEUTICS CORP DELQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 183,246 shares; 2024Q4: 155,714 shares; 2025Q1: 105,228 shares; 2025Q2: 95,482 shares; 2025Q3: 58,186 shares; 2025Q4: 58,186 shares 58,186$28.4M3.95%0Timeline
IRONDISC MEDICINE INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 145,691 shares; 2025Q3: 224,300 shares; 2025Q4: 317,456 shares 317,456$25.2M3.51%+93,156Timeline
IOVAIOVANCE BIOTHERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2025Q4: 7,116,676 shares 7,116,676$19.4M2.7%-501,456Timeline
NVCRNOVOCURE LTDQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2025Q4: 1,298,964 shares 1,298,964$16.8M2.34%+42,805Timeline
SNDXSYNDAX PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 405,193 shares; 2024Q4: 405,193 shares; 2025Q1: 444,367 shares; 2025Q2: 444,367 shares; 2025Q3: 654,930 shares; 2025Q4: 794,507 shares 794,507$16.7M2.32%+139,577Timeline
GOSSGOSSAMER BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2025Q4: 4,471,592 shares 4,471,592$13.9M1.93%-992,757Timeline
CMPXCOMPASS THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: 2,532,419 shares 2,532,419$13.6M1.89%newTimeline
PRTAPROTHENA CORP PLCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2025Q4: 1,320,510 shares 1,320,510$12.6M1.76%-3,518Timeline
MIRMMIRUM PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 64,700 shares; 2024Q4: 64,700 shares; 2025Q1: 64,700 shares; 2025Q2: 64,700 shares; 2025Q3: 64,700 shares; 2025Q4: 156,421 shares 156,421$12.4M1.72%+91,721Timeline
ANNXANNEXON INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: 2,384,192 shares 2,384,192$12M1.67%newTimeline
RAREULTRAGENYX PHARMACEUTICAL INQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 48,750 shares; 2025Q3: 369,531 shares; 2025Q4: 461,294 shares 461,294$10.6M1.48%+91,763Timeline
DNLIDENALI THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 239,809 shares; 2025Q3: 408,006 shares; 2025Q4: 641,239 shares 641,239$10.6M1.47%+233,233Timeline
CDNACAREDX INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: 316,204 shares; 2025Q4: 478,220 shares 478,220$9.01M1.25%+162,016Timeline
EHTHEHEALTH INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2025Q4: 1,531,429 shares 1,531,429$7.04M0.98%-13,190Timeline
ALKSALKERMES PLCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 384,656 shares; 2024Q4: 289,308 shares; 2025Q1: 221,513 shares; 2025Q2: 221,021 shares; 2025Q3: 183,938 shares; 2025Q4: 242,560 shares 242,560$6.79M0.94%+58,622Timeline
CAPRCAPRICOR THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: 226,304 shares 226,304$6.53M0.91%newTimeline
TSHATAYSHA GENE THERAPIES INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2025Q4: 1,183,195 shares 1,183,195$6.51M0.91%-62,838Timeline
ALGNALIGN TECHNOLOGY INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 37,772 shares; 2024Q4: 37,772 shares; 2025Q1: 37,772 shares; 2025Q2: 37,772 shares; 2025Q3: 45,735 shares; 2025Q4: 41,520 shares 41,520$6.48M0.9%-4,215Timeline
AGIOAGIOS PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: 276,578 shares; 2025Q2: 268,783 shares; 2025Q3: 265,497 shares; 2025Q4: 212,499 shares 212,499$5.78M0.81%-52,998Timeline
BCAXBICARA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: 298,575 shares 298,575$5.03M0.7%newTimeline
NUVBNUVATION BIO INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2025Q4: 538,079 shares 538,079$4.82M0.67%-482,468Timeline
ACRSACLARIS THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2025Q4: 1,566,840 shares 1,566,840$4.72M0.66%0Timeline
XENEXENON PHARMACEUTICALS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: 96,519 shares 96,519$4.33M0.6%newTimeline
TVTXTRAVERE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 110,719 shares; 2024Q4: 110,719 shares; 2025Q1: 110,719 shares; 2025Q2: 110,719 shares; 2025Q3: 110,719 shares; 2025Q4: 110,719 shares 110,719$4.23M0.59%0Timeline
EWEDWARDS LIFESCIENCES CORPQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 39,473 shares; 2024Q4: 39,473 shares; 2025Q1: 39,473 shares; 2025Q2: 39,473 shares; 2025Q3: 33,640 shares; 2025Q4: 33,640 shares 33,640$2.87M0.4%0Timeline
NBIXNEUROCRINE BIOSCIENCES INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: 13,334 shares; 2025Q2: 13,334 shares; 2025Q3: 18,117 shares; 2025Q4: 18,117 shares 18,117$2.57M0.36%0Timeline
STOKSTOKE THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 125,861 shares; 2024Q4: 125,861 shares; 2025Q1: 125,861 shares; 2025Q2: 125,861 shares; 2025Q3: 105,427 shares; 2025Q4: 72,022 shares 72,022$2.29M0.32%-33,405Timeline
CRSPCRISPR THERAPEUTICS AGQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: 44,625 shares; 2025Q3: 41,226 shares; 2025Q4: 41,226 shares 41,226$2.16M0.3%0Timeline
BNTXBIONTECH SEQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 25,206 shares; 2024Q4: 25,206 shares; 2025Q1: 25,206 shares; 2025Q2: 25,206 shares; 2025Q3: 19,614 shares; 2025Q4: 19,614 shares 19,614$1.87M0.26%0Timeline
ORKAORUKA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: 59,985 shares; 2025Q4: 59,985 shares 59,985$1.82M0.25%0Timeline
BCYCBICYCLE THERAPEUTICS PLCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 59,582 shares; 2024Q4: 248,934 shares; 2025Q1: 248,934 shares; 2025Q2: 248,934 shares; 2025Q3: 221,071 shares; 2025Q4: 221,071 shares 221,071$1.57M0.22%0Timeline
PYXSPYXIS ONCOLOGY INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 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; 2025Q4: 1,037,421 shares 1,037,421$1.19M0.17%0Timeline
ALDXALDEYRA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 225,465 shares; 2024Q4: 225,465 shares; 2025Q1: 225,465 shares; 2025Q2: 225,465 shares; 2025Q3: 225,465 shares; 2025Q4: 225,465 shares 225,465$1.17M0.16%0Timeline
HUMHUMANA INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 3,985 shares; 2024Q4: 3,985 shares; 2025Q1: 3,985 shares; 2025Q2: 3,985 shares; 2025Q3: 3,985 shares; 2025Q4: 3,985 shares 3,985$1.02M0.14%0Timeline
INSPINSPIRE MED SYS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: 8,772 shares 8,772$809K0.11%newTimeline
CMPSCOMPASS PATHWAYS PLCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: 115,616 shares 115,616$798K0.11%newTimeline
URGNUROGEN PHARMA LTDQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 24,500 shares; 2024Q4: 24,500 shares; 2025Q1: 24,500 shares; 2025Q2: 24,500 shares; 2025Q3: 24,500 shares; 2025Q4: 24,500 shares 24,500$574K0.08%0Timeline
ABEOABEONA THERAPEUTICS INCQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: 12,865 shares; 2024Q4: 108,865 shares; 2025Q1: 108,865 shares; 2025Q2: 108,865 shares; 2025Q3: 108,865 shares; 2025Q4: 108,865 shares 108,865$574K0.08%0Timeline
PRQRPROQR THRAPEUTICS N VQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: 188,807 shares; 2025Q4: 188,807 shares 188,807$381K0.05%0Timeline
GENERATION BIO COGENERATION BIO COQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: not reported; 2025Q1: not reported; 2025Q2: not reported; 2025Q3: not reported; 2025Q4: 15,047 shares 15,047$85.5K0.01%new
AKTXAKARI THERAPEUTICS PLC SPONSORQuarterly shares; oldest to newest; scale is this security's eight-quarter maximum; 2024Q1: restricted; 2024Q2: restricted; 2024Q3: not reported; 2024Q4: 146,024 shares; 2025Q1: 146,024 shares; 2025Q2: 146,024 shares; 2025Q3: 146,024 shares; 2025Q4: 146,024 shares 146,024$42.2K0.01%0Timeline

Sold out in Q4 2025

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

SecurityShares beforeValue beforeType
ALNYALNYLAM PHARMACEUTICALS INC32,320$14.7Mshares
RNAMAVIDITY BIOSCIENCES INC109,831$4.79Mshares
GENERATION BIO COGENERATION BIO CO15,047$92.1Kshares

How Q4 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 0001306923-26-000002 base2026-02-17acceptance time not in the bulk data set