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Prothena (PRTA) Institutional Ownership

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$8.76 +0.18 (+2.10%)
Closing price 08/7/2026 04:00 PM Eastern
Extended Trading
$9.13 +0.37 (+4.27%)
As of 08/7/2026 07:42 PM Eastern
Extended trading is trading that happens on electronic markets outside of regular trading hours. This is a fair market value extended hours price provided by Massive. Learn more.
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Institutional Ownership Changes (13F Filings) for Prothena (NASDAQ:PRTA)

Current
Institutional Ownership
Percentage
97.08%
Number of
Institutional Buyers
(last 12 months)
88
Total
Institutional Inflows
(last 12 months)
$158.87M
Number of
Institutional Sellers
(last 12 months)
51
Total
Institutional Outflows
(last 12 months)
$50.82M
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PRTA Institutional Buying and Selling by Quarter

Prothena Major Shareholders & Ownership History

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Reporting DateMajor Shareholder NameShares HeldMarket Value% of PortfolioQuarterly Change in SharesOwnership in CompanyDetails
7/9/2026 Hennion & Walsh Asset Management Inc.90,795$889K0.0%+2.5%0.173%
7/8/2026 Assenagon Asset Management S.A.62,785$615K0.0%-18.2%0.120%
5/19/2026Bank of America Corp DE393,632$3.83M0.0%-7.9%0.752%
5/18/2026ADAR1 Capital Management LLC1,581,443$15.37M0.9%+8.5%3.021%
5/18/2026Royal Bank of Canada3,171$30K0.0%-28.4%0.006%
5/18/2026Rubric Capital Management LP5,000,000$48.60M0.5%+36.0%9.551%
5/16/2026The Manufacturers Life Insurance Company 12,184$118K0.0%-11.0%0.023%
5/16/2026Quantinno Capital Management LP144,299$1.40M0.0%+39.3%0.276%
5/15/2026Rangeley Capital LLC449,460$4.37M4.0%-14.3%0.859%
5/14/2026Renaissance Technologies LLC607,515$5.91M0.0%+39.5%1.160%
5/14/2026Sei Investments Co.17,248$168K0.0%N/A0.033%
5/7/2026Dimensional Fund Advisors LP782,603$7.61M0.0%+1.0%1.454%
5/5/2026 Bank of New York Mellon Corp136,322$1.33M0.0%+2.7%0.253%
4/30/2026Hsbc Holdings PLC65,070$632K0.0%+134.6%0.121%
4/25/2026 Strs Ohio14,700$143K0.0%-16.5%0.027%
4/24/2026 CHICAGO TRUST Co NA15,057$146K0.0%N/A0.028%
4/21/2026 Penbrook Management LLC271,720$2.64M2.0%N/A0.505%
4/20/2026 Focused Wealth Management Inc207,403$2.02M0.2%+93.0%0.385%
4/16/2026 SG Americas Securities LLC13,522$131K0.0%-78.5%0.025%
3/20/2026Hsbc Holdings PLC27,733$261K0.0%-25.9%0.052%
2/26/2026Seven Fleet Capital Management LP43,300$414K0.3%N/A0.080%
2/19/2026Invesco Ltd.26,609$254K0.0%-15.0%0.049%
2/18/2026ADAR1 Capital Management LLC1,457,764$13.92M1.0%-0.8%2.708%
2/18/2026XTX Topco Ltd54,881$524K0.0%+247.2%0.102%
2/18/2026Virtus Investment Advisers LLC25,679$245K0.1%+14.4%0.048%
2/18/2026Susquehanna Portfolio Strategies LLC58,853$562K0.0%+103.1%0.109%
2/18/2026Polymer Capital Management US LLC23,513$225K0.0%N/A0.044%
2/18/2026 Quadrature Capital Ltd31,090$297K0.0%+14.2%0.058%
2/18/2026Man Group plc269,513$2.57M0.0%+104.2%0.501%
2/18/2026Armistice Capital LLC1,500,000$14.33M0.2%-17.8%2.787%
2/17/2026ADAR1 Capital Management LLC1,457,764$13.92M1.0%-0.8%2.708%
2/17/2026PDT Partners LLC11,334$108K0.0%N/A0.021%
2/17/2026AQR Capital Management LLC186,785$1.78M0.0%-12.9%0.347%
2/17/2026Trexquant Investment LP19,384$185K0.0%-93.1%0.036%
2/17/2026Jump Financial LLC237,828$2.27M0.0%+27.7%0.442%
2/17/2026Price T Rowe Associates Inc. MD81,515$779K0.0%+3.8%0.151%
2/17/2026Monimus Capital Management LP254,122$2.43M1.6%-1.5%0.472%
2/17/2026Diadema Partners LP106,539$1.02M0.2%N/A0.198%
2/17/2026 Russell Investments Group Ltd.99,350$949K0.0%-22.2%0.185%
2/17/2026Atom Investors LP17,026$163K0.0%-20.1%0.032%
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2/17/2026ExodusPoint Capital Management LP87,990$840K0.0%+190.8%0.163%
2/17/2026Royal Bank of Canada4,427$42K0.0%-57.1%0.008%
2/17/2026Graham Capital Management L.P.27,756$265K0.0%-48.0%0.052%
2/17/2026 Persistent Asset Partners Ltd28,589$273K0.1%N/A0.053%
2/16/2026Squarepoint Ops LLC218,041$2.08M0.0%+71.6%0.405%
2/16/2026Mariner LLC577,938$5.52M0.0%-2.2%1.074%
2/16/2026Entropy Technologies LP16,900$161K0.0%N/A0.031%
2/16/2026Barclays PLC183,625$1.75M0.0%+87.2%0.341%
2/13/2026Marshall Wace LLP54,778$523K0.0%N/A0.102%
2/13/2026Rubric Capital Management LP3,677,331$35.12M0.4%+138.7%6.831%
2/13/2026Jacobs Levy Equity Management Inc.978,011$9.34M0.0%+11.6%1.817%
2/13/2026Rafferty Asset Management LLC82,553$788K0.0%N/A0.153%
2/13/2026Headlands Technologies LLC23,352$223K0.0%N/A0.043%
2/13/2026Birchview Capital LP441,019$4.21M2.5%-19.7%0.819%
2/13/2026Charles Schwab Investment Management Inc.357,335$3.41M0.0%+1.9%0.664%
2/13/2026 State Street Corp2,267,802$21.66M0.0%+151.7%4.213%
2/13/2026Martingale Asset Management L P63,453$606K0.0%N/A0.118%
2/13/2026Wells Fargo & Company MN60,108$574K0.0%+48.7%0.112%
2/12/2026DRW Securities LLC11,955$114K0.0%N/A0.022%
2/12/2026MetLife Investment Management LLC25,501$244K0.0%+31.7%0.047%
2/12/2026Renaissance Technologies LLC435,515$4.16M0.0%+17.3%0.809%
2/12/2026Dimensional Fund Advisors LP775,207$7.40M0.0%-3.9%1.440%
2/12/2026Federated Hermes Inc.974,367$9.31M0.0%+40.6%1.810%
2/12/2026 Campbell & CO Investment Adviser LLC94,155$899K0.0%N/A0.175%
2/12/2026Nuveen LLC759,107$7.25M0.0%+13.6%1.410%
2/11/2026DCF Advisers LLC195,747$1.87M0.5%-2.5%0.364%
2/11/2026 Deutsche Bank AG35,482$339K0.0%+5.1%0.066%
2/11/2026 Fox Run Management L.L.C.10,045$96K0.0%-77.3%0.019%
2/11/2026Franklin Resources Inc.47,251$451K0.0%-22.8%0.088%
2/11/2026Los Angeles Capital Management LLC95,406$1M0.0%-20.1%0.177%
2/10/2026Goldman Sachs Group Inc.935,333$8.93M0.0%+164.8%1.738%
2/10/2026Intech Investment Management LLC20,601$197K0.0%+6.3%0.038%
2/9/2026Geode Capital Management LLC1,063,069$10.15M0.0%+4.3%1.975%
2/6/2026 Covestor Ltd21,793$208K0.1%-30.7%0.040%
2/6/2026 PNC Financial Services Group Inc.28,128$269K0.0%+55.1%0.052%
2/6/2026ProShare Advisors LLC10,425$100K0.0%N/A0.019%
2/5/2026 Duncan Williams Asset Management LLC70,281$625K0.2%-20.4%0.131%
2/5/2026 Pinnacle Associates Ltd.62,724$599K0.0%-12.0%0.117%
2/2/2026 Strs Ohio17,600$168K0.0%-38.9%0.033%
1/29/2026UBS Group AG426,360$4.07M0.0%+6.4%0.792%
1/29/2026 Focused Wealth Management Inc107,479$1.03M0.1%+88.1%0.200%
1/22/2026 Massachusetts Financial Services Co. MA45,970$439K0.0%-3.2%0.085%
1/14/2026 Hennion & Walsh Asset Management Inc.91,284$872K0.0%+7.9%0.170%
1/9/2026 SG Americas Securities LLC63,018$602K0.0%+11.1%0.117%
1/9/2026 Assenagon Asset Management S.A.76,769$733K0.0%-14.4%0.143%
1/1/2026JPMorgan Chase & Co.735,765$7.18M0.0%+479.6%1.367%
11/17/2025Jacobs Levy Equity Management Inc.876,528$8.56M0.0%+26.5%1.628%
11/17/2025Armistice Capital LLC1,824,000$17.80M0.3%-18.4%3.388%
11/17/2025Proficio Capital Partners LLC30,136$294K0.0%N/A0.056%
11/17/2025Qube Research & Technologies Ltd254,245$2.48M0.0%-38.7%0.472%
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11/17/2025Palo Alto Investors LP1,324,028$12.92M2.4%+3.9%2.460%
11/17/2025Mariner LLC590,897$5.77M0.0%+52.8%1.098%
11/17/2025Millennium Management LLC621,099$6.06M0.0%+264.1%1.154%
11/17/2025MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd.18,834$184K0.0%-11.2%0.035%
11/17/2025Jain Global LLC11,780$115K0.0%-35.5%0.022%
11/17/2025Bank of America Corp DE277,096$2.70M0.0%+31.4%0.515%
11/17/2025Algert Global LLC445,811$4.35M0.1%+825.9%0.828%
11/17/2025Alliancebernstein L.P.69,607$679K0.0%-20.5%0.129%
11/17/2025Ameriprise Financial Inc.105,536$1.03M0.0%-30.4%0.196%
11/14/2025Creative Planning64,140$626K0.0%+26.8%0.119%


PRTA Institutional Ownership - Frequently Asked Questions

During the previous two years, 157 institutional investors and hedge funds held shares of Prothena. The most heavily invested institutionals were FMR LLC ($111.79M), Wellington Management Group LLP ($64.34M), Rubric Capital Management LP ($48.60M), State Street Corp ($21.66M), Vanguard Group Inc. ($20.01M), Siren L.L.C. ($15.88M), and ADAR1 Capital Management LLC ($15.37M).Learn more on Prothena's institutional investors.

97.08% of Prothena's stock is owned by institutional investors. Learn more on PRTA's institutional investor holdings.

Of the 131 institutional investors that purchased Prothena's stock in the last 24 months, the following investors and hedge funds have bought the highest volume of shares: Rubric Capital Management LP ($5M), Wellington Management Group LLP ($2.51M), JPMorgan Chase & Co. ($1.40M), State Street Corp ($1.37M), Federated Hermes Inc. ($1.26M), Acadian Asset Management LLC ($1.02M), and Rangeley Capital LLC ($715.37K).

Institutional investors have bought a total of 17,867,679 shares in the last 24 months. This purchase volume represents approximately $158.87M in transactions.

Of the 51 institutional investors that sold Prothena's stock in the last 24 months, the following investors and hedge funds have sold the highest volume of shares: ADAR1 Capital Management LLC ($1.93M), Armistice Capital LLC ($736K), Federated Hermes Inc. ($488.27K), Trexquant Investment LP ($259.60K), Prosight Management LP ($247.80K), JPMorgan Chase & Co. ($245.01K), and Dimensional Fund Advisors LP ($187.13K).

Institutional investors have sold a total of 5,419,880 shares in the last 24 months. This volume of shares sold represents approximately $50.82M in transactions.


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Institutional ownership data for NASDAQ:PRTA is compiled from quarterly 13F filings submitted to the U.S. Securities and Exchange Commission (SEC), with the most recent received on 7/9/2026. New 13F filings are added each quarter as they're published.
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