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PRTA Insider Trading

Insider Ownership Percentage: 10.00%
Insider Buying (Last 12 Months): $0.00
Insider Selling (Last 12 Months): $0.00

Prothena Insider Trading History Chart

This chart shows the insider buying and selling history at Prothena by year and by quarter.

Skip ChartChart Data in Insider Trading History Table

Prothena Share Price & Price History

Current Price: $8.97
Price Change: ▼ Price Decrease of -0.1 (-1.10%)
As of 02/24/2026 05:00 PM ET

This chart shows the closing price history over time for PRTA up to the past year.

Skip Chart and Table DataPrice Data in Insider Trading History Table
Days: 30 | 90 | 365

Prothena Insider Trading History

Transaction DateInsider NameTitleBuy/SellNumber of SharesAverage Share PriceTotal TransactionShares Held After TransactionDetails
1/14/2025William P ScullyMajor ShareholderBuy100,000$12.79$1,279,000.00735,993View SEC Filing Icon  
12/31/2024William P ScullyMajor ShareholderBuy32,000$13.01$416,320.00650,193View SEC Filing Icon  
12/20/2024William P ScullyMajor ShareholderBuy2,000$15.91$31,820.00618,693View SEC Filing Icon  
12/18/2024William P ScullyMajor ShareholderBuy73,436$13.93$1,022,963.481,297,693View SEC Filing Icon  
1/24/2024Karin L. WalkerCAOSell5,000$34.00$170,000.00View SEC Filing Icon  
12/20/2023Karin L. WalkerCAOSell5,000$37.19$185,950.00View SEC Filing Icon  
11/30/2023Karin L. WalkerCAOSell5,000$34.00$170,000.00View SEC Filing Icon  
10/25/2023Karin L. WalkerCAOSell5,000$41.04$205,200.00View SEC Filing Icon  
10/11/2023Brandon S. SmithCOOSell4,000$46.75$187,000.00View SEC Filing Icon  
10/4/2023Carol D. KarpinsiderSell5,000$46.62$233,100.00View SEC Filing Icon  
9/27/2023Michael J. MalecekinsiderSell5,000$47.38$236,900.00View SEC Filing Icon  
9/19/2023Karin L. WalkerCAOSell5,000$52.36$261,800.00View SEC Filing Icon  
9/13/2023Brandon S. SmithCOOSell4,000$55.49$221,960.00View SEC Filing Icon  
9/13/2023Hideki GarreninsiderSell2,000$55.48$110,960.00View SEC Filing Icon  
9/6/2023Carol D. KarpinsiderSell5,000$54.76$273,800.00View SEC Filing Icon  
8/30/2023Michael J. MalecekinsiderSell5,000$55.01$275,050.00View SEC Filing Icon  
8/18/2023Karin L. WalkerCAOSell5,000$57.18$285,900.00View SEC Filing Icon  
8/16/2023Brandon S. SmithCOOSell4,000$58.71$234,840.00View SEC Filing Icon  
8/16/2023Hideki GarreninsiderSell2,000$58.74$117,480.00View SEC Filing Icon  
8/2/2023Wagner M. ZagoinsiderSell4,000$67.05$268,200.00View SEC Filing Icon  
7/26/2023Michael J. MalecekinsiderSell5,000$62.33$311,650.00View SEC Filing Icon  
7/19/2023Karin L. WalkerCAOSell5,000$69.19$345,950.00View SEC Filing Icon  
7/12/2023Brandon S. SmithCOOSell4,000$67.51$270,040.00View SEC Filing Icon  
7/12/2023Hideki GarreninsiderSell2,000$67.51$135,020.00View SEC Filing Icon  
7/5/2023Carol D. KarpinsiderSell5,000$68.13$340,650.00View SEC Filing Icon  
7/3/2023Dennis J SelkoeDirectorSell5,000$67.43$337,150.002,845View SEC Filing Icon  
6/28/2023Michael J. MalecekinsiderSell5,000$69.82$349,100.00View SEC Filing Icon  
6/16/2023Hideki GarreninsiderSell7,331$74.00$542,494.00View SEC Filing Icon  
6/14/2023Brandon S. SmithCOOSell5,333$73.98$394,535.34View SEC Filing Icon  
6/14/2023Hideki GarreninsiderSell4,669$74.22$346,533.18View SEC Filing Icon  
6/7/2023Wagner M. ZagoinsiderSell19,000$71.06$1,350,140.00View SEC Filing Icon  
5/31/2023Michael J. MalecekinsiderSell5,000$64.64$323,200.00View SEC Filing Icon  
5/19/2023Karin L. WalkerCAOSell5,000$74.00$370,000.00View SEC Filing Icon  
5/17/2023Gene G KinneyCEOSell45,000$73.70$3,316,500.0012,793View SEC Filing Icon  
5/17/2023Tran NguyenCFOSell95,000$73.99$7,029,050.003,200View SEC Filing Icon  
5/3/2023Dennis J SelkoeDirectorSell15,000$57.00$855,000.002,845View SEC Filing Icon  
4/26/2023Michael J. MalecekinsiderSell5,000$53.46$267,300.00View SEC Filing Icon  
4/19/2023Karin L. WalkerCAOSell5,000$52.90$264,500.00View SEC Filing Icon  
3/29/2023Michael J. MalecekinsiderSell5,000$49.02$245,100.00View SEC Filing Icon  
3/20/2023Karin L. WalkerCAOSell5,000$47.72$238,600.00View SEC Filing Icon  
3/15/2023Karin L. WalkerCAOSell20,000$48.42$968,400.00View SEC Filing Icon  
3/15/2023Michael J. MalecekinsiderSell15,000$48.44$726,600.00View SEC Filing Icon  
3/15/2023Tran NguyenCFOSell10,000$48.43$484,300.003,200View SEC Filing Icon  
See Full Table

SEC Filings (Institutional Ownership Changes) for Prothena (NASDAQ:PRTA)

97.08% of Prothena stock is owned by institutions. Institutional ownership can be a sign of analyst confidence in the fundamentals of the stock.

Institutional Buying and Selling by Quarter

This chart shows the instiutional buying and selling at PRTA by year and by quarter.

Skip Institutional Buying and Selling Chart and Table DataRead Chart Data in Institutional Trading History Table

Prothena Institutional Trading History

Reporting DateHedge FundShares HeldMarket Value% of PortfolioQuarterly Change in SharesOwnership in CompanyDetails
2/19/2026Invesco Ltd.26,609$0.25M0.0%-15.0%0.049%Search for SEC Filing on Google Icon
2/18/2026ADAR1 Capital Management LLC1,457,764$13.92M1.0%-0.8%2.708%Search for SEC Filing on Google Icon
2/18/2026XTX Topco Ltd54,881$0.52M0.0%+247.2%0.102%Search for SEC Filing on Google Icon
2/18/2026Virtus Investment Advisers LLC25,679$0.25M0.1%+14.4%0.048%Search for SEC Filing on Google Icon
2/18/2026Susquehanna Portfolio Strategies LLC58,853$0.56M0.0%+103.1%0.109%Search for SEC Filing on Google Icon
2/18/2026Polymer Capital Management US LLC23,513$0.23M0.0%N/A0.044%Search for SEC Filing on Google Icon
2/18/2026Quadrature Capital Ltd31,090$0.30M0.0%+14.2%0.058%Search for SEC Filing on Google Icon
2/18/2026Man Group plc269,513$2.57M0.0%+104.2%0.501%Search for SEC Filing on Google Icon
2/18/2026Armistice Capital LLC1,500,000$14.33M0.2%-17.8%2.787%Search for SEC Filing on Google Icon
2/17/2026ADAR1 Capital Management LLC1,457,764$13.92M1.0%-0.8%2.708%Search for SEC Filing on Google Icon
2/17/2026PDT Partners LLC11,334$0.11M0.0%N/A0.021%Search for SEC Filing on Google Icon
2/17/2026AQR Capital Management LLC186,785$1.78M0.0%-12.9%0.347%Search for SEC Filing on Google Icon
2/17/2026Trexquant Investment LP19,384$0.19M0.0%-93.1%0.036%Search for SEC Filing on Google Icon
2/17/2026Jump Financial LLC237,828$2.27M0.0%+27.7%0.442%Search for SEC Filing on Google Icon
2/17/2026Price T Rowe Associates Inc. MD81,515$0.78M0.0%+3.8%0.151%Search for SEC Filing on Google Icon
2/17/2026Monimus Capital Management LP254,122$2.43M1.6%-1.5%0.472%Search for SEC Filing on Google Icon
2/17/2026Diadema Partners LP106,539$1.02M0.2%N/A0.198%Search for SEC Filing on Google Icon
2/17/2026Russell Investments Group Ltd.99,350$0.95M0.0%-22.2%0.185%Search for SEC Filing on Google Icon
2/17/2026Atom Investors LP17,026$0.16M0.0%-20.1%0.032%Search for SEC Filing on Google Icon
2/17/2026ExodusPoint Capital Management LP87,990$0.84M0.0%+190.8%0.163%Search for SEC Filing on Google Icon
2/17/2026Royal Bank of Canada4,427$42K0.0%-57.1%0.008%Search for SEC Filing on Google Icon
2/17/2026Graham Capital Management L.P.27,756$0.27M0.0%-48.0%0.052%Search for SEC Filing on Google Icon
2/17/2026Persistent Asset Partners Ltd28,589$0.27M0.1%N/A0.053%Search for SEC Filing on Google Icon
2/16/2026Squarepoint Ops LLC218,041$2.08M0.0%+71.6%0.405%Search for SEC Filing on Google Icon
2/16/2026Mariner LLC577,938$5.52M0.0%-2.2%1.074%Search for SEC Filing on Google Icon
2/16/2026Entropy Technologies LP16,900$0.16M0.0%N/A0.031%Search for SEC Filing on Google Icon
2/16/2026Barclays PLC183,625$1.75M0.0%+87.2%0.341%Search for SEC Filing on Google Icon
2/13/2026Marshall Wace LLP54,778$0.52M0.0%N/A0.102%Search for SEC Filing on Google Icon
2/13/2026Rubric Capital Management LP3,677,331$35.12M0.4%+138.7%6.831%Search for SEC Filing on Google Icon
2/13/2026Jacobs Levy Equity Management Inc.978,011$9.34M0.0%+11.6%1.817%Search for SEC Filing on Google Icon
2/13/2026Rafferty Asset Management LLC82,553$0.79M0.0%N/A0.153%Search for SEC Filing on Google Icon
2/13/2026Headlands Technologies LLC23,352$0.22M0.0%N/A0.043%Search for SEC Filing on Google Icon
2/13/2026Birchview Capital LP441,019$4.21M2.5%-19.7%0.819%Search for SEC Filing on Google Icon
2/13/2026Charles Schwab Investment Management Inc.357,335$3.41M0.0%+1.9%0.664%Search for SEC Filing on Google Icon
2/13/2026State Street Corp2,267,802$21.66M0.0%+151.7%4.213%Search for SEC Filing on Google Icon
2/13/2026Martingale Asset Management L P63,453$0.61M0.0%N/A0.118%Search for SEC Filing on Google Icon
2/13/2026Wells Fargo & Company MN60,108$0.57M0.0%+48.7%0.112%Search for SEC Filing on Google Icon
2/12/2026DRW Securities LLC11,955$0.11M0.0%N/A0.022%Search for SEC Filing on Google Icon
2/12/2026MetLife Investment Management LLC25,501$0.24M0.0%+31.7%0.047%Search for SEC Filing on Google Icon
2/12/2026Renaissance Technologies LLC435,515$4.16M0.0%+17.3%0.809%Search for SEC Filing on Google Icon
2/12/2026Dimensional Fund Advisors LP775,207$7.40M0.0%-3.9%1.440%Search for SEC Filing on Google Icon
2/12/2026Federated Hermes Inc.974,367$9.31M0.0%+40.6%1.810%Search for SEC Filing on Google Icon
2/12/2026Campbell & CO Investment Adviser LLC94,155$0.90M0.0%N/A0.175%Search for SEC Filing on Google Icon
2/12/2026Nuveen LLC759,107$7.25M0.0%+13.6%1.410%Search for SEC Filing on Google Icon
2/11/2026DCF Advisers LLC195,747$1.87M0.5%-2.5%0.364%Search for SEC Filing on Google Icon
2/11/2026Deutsche Bank AG35,482$0.34M0.0%+5.1%0.066%Search for SEC Filing on Google Icon
2/11/2026Fox Run Management L.L.C.10,045$96K0.0%-77.3%0.019%Search for SEC Filing on Google Icon
2/11/2026Franklin Resources Inc.47,251$0.45M0.0%-22.8%0.088%Search for SEC Filing on Google Icon
2/11/2026Los Angeles Capital Management LLC95,406$1M0.0%-20.1%0.177%Search for SEC Filing on Google Icon
2/10/2026Goldman Sachs Group Inc.935,333$8.93M0.0%+164.8%1.738%Search for SEC Filing on Google Icon
2/10/2026Intech Investment Management LLC20,601$0.20M0.0%+6.3%0.038%Search for SEC Filing on Google Icon
2/9/2026Geode Capital Management LLC1,063,069$10.15M0.0%+4.3%1.975%Search for SEC Filing on Google Icon
2/6/2026Covestor Ltd21,793$0.21M0.1%-30.7%0.040%Search for SEC Filing on Google Icon
2/6/2026PNC Financial Services Group Inc.28,128$0.27M0.0%+55.1%0.052%Search for SEC Filing on Google Icon
2/6/2026ProShare Advisors LLC10,425$100K0.0%N/A0.019%Search for SEC Filing on Google Icon
2/5/2026Duncan Williams Asset Management LLC70,281$0.63M0.2%-20.4%0.131%Search for SEC Filing on Google Icon
2/5/2026Pinnacle Associates Ltd.62,724$0.60M0.0%-12.0%0.117%Search for SEC Filing on Google Icon
2/2/2026Strs Ohio17,600$0.17M0.0%-38.9%0.033%Search for SEC Filing on Google Icon
1/29/2026UBS Group AG426,360$4.07M0.0%+6.4%0.792%Search for SEC Filing on Google Icon
1/29/2026Focused Wealth Management Inc107,479$1.03M0.1%+88.1%0.200%Search for SEC Filing on Google Icon
1/22/2026Massachusetts Financial Services Co. MA45,970$0.44M0.0%-3.2%0.085%Search for SEC Filing on Google Icon
1/14/2026Hennion & Walsh Asset Management Inc.91,284$0.87M0.0%+7.9%0.170%Search for SEC Filing on Google Icon
1/9/2026SG Americas Securities LLC63,018$0.60M0.0%+11.1%0.117%Search for SEC Filing on Google Icon
1/9/2026Assenagon Asset Management S.A.76,769$0.73M0.0%-14.4%0.143%Search for SEC Filing on Google Icon
1/1/2026JPMorgan Chase & Co.735,765$7.18M0.0%+479.6%1.367%Search for SEC Filing on Google Icon
11/17/2025Jacobs Levy Equity Management Inc.876,528$8.56M0.0%+26.5%1.628%Search for SEC Filing on Google Icon
11/17/2025Armistice Capital LLC1,824,000$17.80M0.3%-18.4%3.388%Search for SEC Filing on Google Icon
11/17/2025Proficio Capital Partners LLC30,136$0.29M0.0%N/A0.056%Search for SEC Filing on Google Icon
11/17/2025Qube Research & Technologies Ltd254,245$2.48M0.0%-38.7%0.472%Search for SEC Filing on Google Icon
11/17/2025Palo Alto Investors LP1,324,028$12.92M2.4%+3.9%2.460%Search for SEC Filing on Google Icon
11/17/2025Mariner LLC590,897$5.77M0.0%+52.8%1.098%Search for SEC Filing on Google Icon
11/17/2025Millennium Management LLC621,099$6.06M0.0%+264.1%1.154%Search for SEC Filing on Google Icon
11/17/2025MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd.18,834$0.18M0.0%-11.2%0.035%Search for SEC Filing on Google Icon
11/17/2025Jain Global LLC11,780$0.12M0.0%-35.5%0.022%Search for SEC Filing on Google Icon
11/17/2025Bank of America Corp DE277,096$2.70M0.0%+31.4%0.515%Search for SEC Filing on Google Icon
11/17/2025Algert Global LLC445,811$4.35M0.1%+825.9%0.828%Search for SEC Filing on Google Icon
11/17/2025Alliancebernstein L.P.69,607$0.68M0.0%-20.5%0.129%Search for SEC Filing on Google Icon
11/17/2025Ameriprise Financial Inc.105,536$1.03M0.0%-30.4%0.196%Search for SEC Filing on Google Icon
11/14/2025Creative Planning64,140$0.63M0.0%+26.8%0.119%Search for SEC Filing on Google Icon
11/14/2025Raymond James Financial Inc.22,032$0.22M0.0%+63.2%0.041%Search for SEC Filing on Google Icon
11/14/2025Sandia Investment Management LP29,950$0.29M0.9%N/A0.056%Search for SEC Filing on Google Icon
11/14/2025Rubric Capital Management LP1,540,373$15.03M0.2%N/A2.862%Search for SEC Filing on Google Icon
11/14/2025Man Group plc131,973$1.29M0.0%+208.7%0.245%Search for SEC Filing on Google Icon
11/14/2025ADAR1 Capital Management LLC1,469,098$14.34M1.3%-56.5%2.729%Search for SEC Filing on Google Icon
11/14/2025Arizona PSPRS Trust27,700$0.29M0.0%N/A0.051%Search for SEC Filing on Google Icon
11/14/2025Brooklyn Investment Group12,569$0.12M0.0%+13.1%0.023%Search for SEC Filing on Google Icon
11/14/2025Two Sigma Investments LP426,605$4.16M0.0%+111.8%0.793%Search for SEC Filing on Google Icon
11/14/2025Squarepoint Ops LLC127,033$1.24M0.0%-39.3%0.236%Search for SEC Filing on Google Icon
11/14/2025Prosight Management LP20,000$0.20M0.0%-92.5%0.037%Search for SEC Filing on Google Icon
11/13/2025Arrowstreet Capital Limited Partnership654,294$6.39M0.0%N/A1.215%Search for SEC Filing on Google Icon
11/13/2025UBS Group AG400,847$3.91M0.0%+560.8%0.745%Search for SEC Filing on Google Icon
11/13/2025BNP Paribas Financial Markets228,010$2.23M0.0%+386.7%0.424%Search for SEC Filing on Google Icon
11/13/2025Franklin Resources Inc.61,172$0.60M0.0%+9.1%0.114%Search for SEC Filing on Google Icon
11/13/2025Legal & General Group Plc3,599$35K0.0%-61.4%0.007%Search for SEC Filing on Google Icon
11/13/2025Russell Investments Group Ltd.127,757$1.25M0.0%+32.8%0.237%Search for SEC Filing on Google Icon
11/13/2025Pinnacle Associates Ltd.71,261$0.70M0.0%-3.8%0.132%Search for SEC Filing on Google Icon
11/12/2025DCF Advisers LLC200,747$1.96M0.6%+28.3%0.373%Search for SEC Filing on Google Icon
11/12/2025Barclays PLC98,075$0.96M0.0%-15.3%0.182%Search for SEC Filing on Google Icon
11/12/2025Dimensional Fund Advisors LP806,988$7.88M0.0%-16.1%1.499%Search for SEC Filing on Google Icon
11/12/2025Intech Investment Management LLC19,388$0.19M0.0%+5.5%0.036%Search for SEC Filing on Google Icon
Data available starting January 2016

See Full Table
Prothena logo
Prothena Corporation plc, a late-stage clinical biotechnology company, focuses on discovery and development of novel therapies to treat diseases caused by protein dysregulation in the United States. The company is involved in developing birtamimab, an investigational humanized antibody that is in Phase III clinical trial for the treatment of AL amyloidosis; Prasinezumab, a humanized monoclonal antibody, for the treatment of Parkinson's disease and other related synucleinopathies which is in Phase IIb clinical trial; NNC6019 that is in Phase lI clinical trial for the treatment of ATTR amyloidosis; and BMS-986446 and PRX012, which is in Phase I clinical trial for the treatment of Alzheimer's disease. Its discovery and preclinical programs include PRX123, a dual Aß-Tau vaccine for the treatment and prevention of Alzheimer's disease; and PRX019 for the treatment of neurogenerative diseases, as well as TDP-43 for the treatment of amyotrophic lateral sclerosis. Prothena Corporation plc has a license, development, and commercialization agreement with F. Hoffmann-La Roche Ltd. and Hoffmann-La Roche Inc. to develop and commercialize antibodies that target a-synuclein, including prasinezumab; and a collaboration agreement with Bristol-Myers Squibb to develop and commercialize antibodies targeting tau, TDP-43. The company was incorporated in 2012 and is based in Dublin, Ireland.
Read More on Prothena

Today's Range

Now: $8.97
Low: $8.75
High: $9.30

50 Day Range

MA: $9.24
Low: $8.35
High: $10.34

52 Week Range

Now: $8.97
Low: $4.32
High: $16.16

Volume

448,815 shs

Average Volume

470,473 shs

Market Capitalization

$482.86 million

P/E Ratio

N/A

Dividend Yield

N/A

Beta

N/A

Who are the company insiders with the largest holdings of Prothena?

Prothena's top insider shareholders include:
  1. William P Scully (Major Shareholder)
Learn More about top insider investors at Prothena.

Who are the major institutional investors of Prothena?

Prothena's top institutional shareholders include:
  1. Rubric Capital Management LP — 6.83%
  2. State Street Corp — 4.21%
  3. Armistice Capital LLC — 2.79%
  4. ADAR1 Capital Management LLC — 2.71%
  5. ADAR1 Capital Management LLC — 2.71%
  6. Geode Capital Management LLC — 1.97%
Learn More about top institutional investors of Prothena stock.

Which major investors are selling Prothena stock?

During the previous quarter, PRTA stock was sold by these institutional investors:
  1. Armistice Capital LLC
  2. Trexquant Investment LP
  3. Group One Trading LLC
  4. Birchview Capital LP
  5. Simplex Trading LLC
  6. Jane Street Group LLC
  7. Fox Run Management L.L.C.
  8. Dimensional Fund Advisors LP

Which major investors are buying Prothena stock?

In the last quarter, PRTA stock was bought by institutional investors including:
  1. Rubric Capital Management LP
  2. State Street Corp
  3. Goldman Sachs Group Inc.
  4. Federated Hermes Inc.
  5. Man Group plc
  6. Diadema Partners LP
  7. Jacobs Levy Equity Management Inc.
  8. Campbell & CO Investment Adviser LLC