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Prothena Corp Public Ltd Co

PRTA
Exchange
Nasdaq
Industry
Pharmaceutical Preparations
SEC CIK
0001559053

In the last 90 days, Prothena Corp Public Ltd Co insiders filed 4 open-market purchases and 2 sales; 187 institutions reported holding it in 13F filings for Q2 2026, worth $462.7M in total; no superinvestor holds it.

13F holders, Q3 2025

Institutional positions in Prothena Corp Public Ltd Co as of Sep 30, 2025. Investment managers with $100 million or more in US stocks report their long positions on Form 13F within 45 days after each quarter ends. How 13F works

Institutional holders
187
−1 vs. Q2 2025
Shares held
42.6M
+896.5K (+2.1%) vs. Q2 2025
Total value
$415.8M
+$162.6M (+64.2%) vs. Q2 2025
New holders
31
58 more added
Sold out
32
61 more reduced

1 institution that held it in Q2 2025 haven't filed for Q3 2025 yet. Not filing isn't selling, so they aren't counted as sold out or in the changes above.

Compare with Q2 2025: new holders, sold out and not filed yet

Holders and value by quarter

Institutions reporting PRTA on Form 13F each quarter since Q1 2021, and the total value they reported. Values are as of each quarter end, so they also move with the share price.

Institutional holdersQ3 2025: 187 institutions
Q1 2021: 146 institutionsQ2 2021: 156 institutionsQ3 2021: 192 institutionsQ4 2021: 196 institutionsQ1 2022: 174 institutionsQ2 2022: 167 institutionsQ3 2022: 183 institutionsQ4 2022: 201 institutionsQ1 2023: 192 institutionsQ2 2023: 196 institutionsQ3 2023: 187 institutionsQ4 2023: 187 institutionsQ1 2024: 169 institutionsQ2 2024: 160 institutionsQ3 2024: 164 institutionsQ4 2024: 171 institutionsQ1 2025: 161 institutionsQ2 2025: 189 institutionsQ3 2025: 187 institutionsQ4 2025: 182 institutionsQ1 2026: 186 institutionsQ2 2026: 187 institutions
Value heldQ3 2025: $415.8M
Q1 2021: $1.00BQ2 2021: $2.08BQ3 2021: $2.92BQ4 2021: $2.12BQ1 2022: $1.61BQ2 2022: $1.21BQ3 2022: $2.69BQ4 2022: $2.98BQ1 2023: $2.51BQ2 2023: $3.54BQ3 2023: $2.56BQ4 2023: $1.95BQ1 2024: $1.33BQ2 2024: $1.05BQ3 2024: $855.8MQ4 2024: $741.3MQ1 2025: $647.2MQ2 2025: $253.6MQ3 2025: $415.8MQ4 2025: $451.6MQ1 2026: $459.5MQ2 2026: $462.7M
Institutions holding PRTA and their total value by quarter
QuarterHoldersValue
Q2 2026187$462.7M
Q1 2026186$459.5M
Q4 2025182$451.6M
Q3 2025187$415.8M
Q2 2025189$253.6M
Q1 2025161$647.2M
Q4 2024171$741.3M
Q3 2024164$855.8M
Q2 2024160$1.05B
Q1 2024169$1.33B
Q4 2023187$1.95B
Q3 2023187$2.56B
Q2 2023196$3.54B
Q1 2023192$2.51B
Q4 2022201$2.98B
Q3 2022183$2.69B
Q2 2022167$1.21B
Q1 2022174$1.61B
Q4 2021196$2.12B
Q3 2021192$2.92B
Q2 2021156$2.08B
Q1 2021146$1.00B

Institutions, Q3 2025

Shares, value and share of portfolio for each institution holding Prothena Corp Public Ltd Co; share changes are against Q2 2025.

Institutions holding PRTA in Q3 2025
InstitutionSharesValue% of portfolioChange in sharesAction
FMR LLC7,901,218$77.1M0.00%00.0%Unchanged
BlackRock, Inc.3,598,417$35.1M0.00%−340,981−8.7%Reduced
Vanguard Group Inc2,049,849$20.0M0.00%−126,378−5.8%Reduced
Armistice Capital, LLC1,824,000$17.8M0.56%−412,000−18.4%Reduced
Rubric Capital Management LP1,540,373$15.0M0.20%+1,540,373New
ADAR1 Capital Management, LLC1,469,098$14.3M1.42%−1,905,911−56.5%Reduced
Palo Alto Investors LP1,324,028$12.9M2.39%+49,275+3.9%Added
D. E. Shaw & Co., Inc.1,315,418$12.8M0.01%+923,923+236.0%Added
Acadian Asset Management LLC1,239,242$12.1M0.02%+221,065+21.7%Added
Geode Capital Management, LLC1,019,483$9.95M0.00%+86,037+9.2%Added
State Street Corp901,038$8.79M0.00%−103,964−10.3%Reduced
Jacobs Levy Equity Management, Inc876,528$8.55M0.03%+183,374+26.5%Added
Dimensional Fund Advisors LP806,988$7.88M0.00%−155,351−16.1%Reduced
Morgan Stanley799,674$7.80M0.00%−153,582−16.1%Reduced
Citadel Advisors LLC767,105$7.49M0.01%−380,517−33.2%Reduced
JPMorgan Chase & Co735,765$7.18M0.00%+608,814+479.6%Added
Federated Hermes, Inc.692,818$6.76M0.01%−488,269−41.3%Reduced
Nuveen, LLC668,290$6.52M0.00%+546,135+447.1%Added
Arrowstreet Capital, Limited Partnership654,294$6.39M0.00%+654,294New
Point72 Asset Management, L.P.646,746$6.31M0.01%+646,746New
Millennium Management LLC621,099$6.06M0.00%+450,520+264.1%Added
Jane Street Group, LLC619,792$6.05M0.01%+502,339+427.7%Added
Mariner, LLC590,897$5.77M0.01%+204,189+52.8%Added
Rangeley Capital, LLC560,457$5.47M5.14%−154,910−21.7%Reduced
Birchview Capital, LP549,019$5.36M4.05%+98,000+21.7%Added
Algert Global LLC445,811$4.35M0.07%+397,661+825.9%Added
Two Sigma Investments, LP426,605$4.16M0.01%+225,155+111.8%Added
UBS Group AG400,847$3.91M0.00%+340,183+560.8%Added
Renaissance Technologies LLC371,300$3.62M0.00%+281,100+311.6%Added
Goldman Sachs Group Inc353,221$3.45M0.00%−175,102−33.1%Reduced
Charles Schwab Investment Management Inc350,821$3.42M0.00%+75,737+27.5%Added
Northern Trust Corp334,657$3.27M0.00%+1030.0%Added
Trexquant Investment LP278,979$2.72M0.03%−273,847−49.5%Reduced
Bank of America Corp277,096$2.70M0.00%+66,151+31.4%Added
Two Sigma Advisers, LP265,700$2.59M0.01%+125,900+90.1%Added
Monimus Capital Management, LP258,056$2.52M1.87%+51,581+25.0%Added
Qube Research & Technologies Ltd254,245$2.48M0.00%−160,583−38.7%Reduced
BNP Paribas Arbitrage, SA228,010$2.23M0.00%+181,166+386.7%Added
AQR Capital Management LLC214,542$2.09M0.00%+214,542New
DCF Advisers, LLC200,747$1.96M0.74%+44,247+28.3%Added
Cubist Systematic Strategies, LLC190,949$1.86M0.03%−310,815−61.9%Reduced
Jump Financial, LLC186,247$1.82M0.02%+186,247New
Susquehanna International Group, LLP157,447$1.54M0.00%+65,497+71.2%Added
Bank of New York Mellon Corp153,800$1.50M0.00%+5,450+3.7%Added
Man Group plc131,973$1.29M0.00%+89,221+208.7%Added
Russell Investments Group, Ltd.127,757$1.25M0.00%+31,561+32.8%Added
Squarepoint Ops LLC127,033$1.24M0.00%−82,216−39.3%Reduced
Los Angeles Capital Management LLC119,424$1.17M0.00%+102,722+615.0%Added
Janney Montgomery Scott LLC106,898$1.04M0.00%+106,898New
Ameriprise Financial Inc105,536$1.03M0.00%−46,007−30.4%Reduced
Quantinno Capital Management LP101,187$987.6K0.00%+41,569+69.7%Added
Barclays PLC98,075$957.2K0.00%−17,773−15.3%Reduced
Assenagon Asset Management S.A.89,704$875.5K0.00%+89,704New
Duncan Williams Asset Management, LLC88,339$862.2K0.24%00.0%Unchanged
Hennion & Walsh Asset Management, Inc.84,598$825.7K0.03%−1,556−1.8%Reduced
Price T Rowe Associates Inc78,547$767.0K0.00%+7,500+10.6%Added
American Century Companies Inc72,239$705.1K0.00%+12,274+20.5%Added
Pinnacle Associates Ltd71,261$695.5K0.01%−2,818−3.8%Reduced
Monaco Asset Management SAM70,000$683.2K0.25%00.0%Unchanged
Alliancebernstein L.P.69,607$679.4K0.00%−17,980−20.5%Reduced
Creative Planning64,140$626.0K0.00%+13,571+26.8%Added
Rhumbline Advisers62,042$605.5K0.00%−963−1.5%Reduced
Franklin Resources Inc61,172$597.0K0.00%+5,094+9.1%Added
Caption Management, LLC61,009$595.4K0.03%−4,091−6.3%Reduced
Focused Wealth Management, Inc57,129$557.6K0.06%+25,000+77.8%Added
SG Americas Securities, LLC56,719$554.0K0.00%+4,778+9.2%Added
Engineers Gate Manager LP56,080$547.3K0.01%+15,113+36.9%Added
Balyasny Asset Management LLC55,764$544.3K0.00%−520,028−90.3%Reduced
Graham Capital Management, L.P.53,393$521.1K0.02%+19,351+56.8%Added
Quinn Opportunity Partners LLC50,000$488.0K0.04%00.0%Unchanged
Massachusetts Financial Services Co47,489$463.5K0.00%+3,125+7.0%Added
Fox Run Management, L.L.C.44,332$432.7K0.07%+44,332New
Public Employees Retirement System of Ohio42,158$411.5K0.00%00.0%Unchanged
Simplex Trading, LLC42,044$410.0K0.01%−1,220−2.8%Reduced
Wells Fargo & Company40,430$394.6K0.00%−790−1.9%Reduced
HSBC Holdings PLC37,432$364.6K0.00%−8,615−18.7%Reduced
Deutsche Bank AG33,773$329.6K0.00%−5,828−14.7%Reduced
Covestor Ltd31,432$307.0K0.17%−10,863−25.7%Reduced
Invesco Ltd.31,303$305.5K0.00%−5,582−15.1%Reduced
HRT Financial LP31,106$303.0K0.00%+31,106New
ExodusPoint Capital Management, LP30,254$295.3K0.00%−28,664−48.7%Reduced
Proficio Capital Partners LLC30,136$294.1K0.02%+30,136New
Boothbay Fund Management, LLC30,000$292.8K0.01%+30,000New
Arizona PSPRS Trust27,700$292.5K0.01%+27,700New
Sandia Investment Management LP29,950$292.3K0.87%+29,950New
RBF Capital, LLC29,200$285.0K0.01%00.0%Unchanged
Susquehanna Portfolio Strategies, LLC28,975$282.8K0.00%−42,693−59.6%Reduced
STRS Ohio28,800$281.1K0.00%+12,400+75.6%Added
Cambridge Investment Research Advisors, Inc.27,513$269.0K0.00%+202+0.7%Added
Quadrature Capital Ltd27,215$265.3K0.00%+3,463+14.6%Added
Tudor Investment Corp Et Al27,073$264.2K0.00%−926−3.3%Reduced
Alps Advisors Inc25,727$251.1K0.00%−3,301−11.4%Reduced
Rock Springs Capital Management LP25,398$247.9K0.01%−467,203−94.8%Reduced
Purkiss Capital Advisors LLC25,386$247.8K0.12%+482+1.9%Added
Edgewood Management LLC24,060$234.8K0.00%00.0%Unchanged
Virtus Investment Advisers, Inc.22,443$219.0K0.06%+3,896+21.0%Added
Raymond James Financial Inc22,032$215.0K0.00%+8,536+63.2%Added
Atom Investors LP21,315$208.0K0.02%+21,315New
Handelsbanken Fonder AB20,900$204.0K0.00%00.0%Unchanged
Mogy Joel R Investment Counsel Inc20,750$202.5K0.01%00.0%Unchanged