Prothena (PRTA) Institutional Ownership

$9.33 +0.24 (+2.64%)

As of 08/28/2026 04:00 PM Eastern

Current Institutional Ownership Percentage: 97.08%
Number of Institutional Buyers (last 12 months): 77
Total Institutional Inflows (last 12 months): $136.40M

Number of Institutional Sellers (last 12 months): 46
Total Institutional Outflows (last 12 months): $47.76M

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PRTA Institutional Buying and Selling by Quarter

Prothena Major Shareholders & Ownership History

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Reporting Date	Major Shareholder Name	Shares Held	Market Value	% of Portfolio	Quarterly Change in Shares	Ownership in Company
8/24/2026	California State Teachers Retirement System	6,001	$613K	0.0%	+151.8%	0.011%
8/20/2026	Headlands Technologies LLC	15,077	$148K	0.0%	N/A	0.029%
8/18/2026	Public Employees Retirement System of Ohio	42,158	$413K	0.0%	N/A	0.081%
8/10/2026	Great Lakes Advisors LLC	28,733	$281K	0.0%	N/A	0.055%
7/9/2026	Hennion & Walsh Asset Management Inc.	90,795	$889K	0.0%	+2.5%	0.173%
7/8/2026	Assenagon Asset Management S.A.	62,785	$615K	0.0%	-18.2%	0.120%
5/19/2026	Bank of America Corp DE	393,632	$3.83M	0.0%	-7.9%	0.752%
5/18/2026	ADAR1 Capital Management LLC	1,581,443	$15.37M	0.9%	+8.5%	3.021%
5/18/2026	Royal Bank of Canada	3,171	$30K	0.0%	-28.4%	0.006%
5/18/2026	Rubric Capital Management LP	5,000,000	$48.60M	0.5%	+36.0%	9.551%
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5/16/2026	The Manufacturers Life Insurance Company	12,184	$118K	0.0%	-11.0%	0.023%
5/16/2026	Quantinno Capital Management LP	144,299	$1.40M	0.0%	+39.3%	0.276%
5/15/2026	Rangeley Capital LLC	449,460	$4.37M	4.0%	-14.3%	0.859%
5/14/2026	Renaissance Technologies LLC	607,515	$5.91M	0.0%	+39.5%	1.160%
5/14/2026	Sei Investments Co.	17,248	$168K	0.0%	N/A	0.033%
5/7/2026	Dimensional Fund Advisors LP	782,603	$7.61M	0.0%	+1.0%	1.454%
5/5/2026	Bank of New York Mellon Corp	136,322	$1.33M	0.0%	+2.7%	0.253%
4/30/2026	Hsbc Holdings PLC	65,070	$632K	0.0%	+134.6%	0.121%
4/25/2026	Strs Ohio	14,700	$143K	0.0%	-16.5%	0.027%
4/24/2026	CHICAGO TRUST Co NA	15,057	$146K	0.0%	N/A	0.028%
4/21/2026	Penbrook Management LLC	271,720	$2.64M	2.0%	N/A	0.505%
4/20/2026	Focused Wealth Management Inc	207,403	$2.02M	0.2%	+93.0%	0.385%
4/16/2026	SG Americas Securities LLC	13,522	$131K	0.0%	-78.5%	0.025%
3/20/2026	Hsbc Holdings PLC	27,733	$261K	0.0%	-25.9%	0.052%
2/26/2026	Seven Fleet Capital Management LP	43,300	$414K	0.3%	N/A	0.080%
2/19/2026	Invesco Ltd.	26,609	$254K	0.0%	-15.0%	0.049%
2/18/2026	ADAR1 Capital Management LLC	1,457,764	$13.92M	1.0%	-0.8%	2.708%
2/18/2026	XTX Topco Ltd	54,881	$524K	0.0%	+247.2%	0.102%
2/18/2026	Virtus Investment Advisers LLC	25,679	$245K	0.1%	+14.4%	0.048%
2/18/2026	Susquehanna Portfolio Strategies LLC	58,853	$562K	0.0%	+103.1%	0.109%
2/18/2026	Polymer Capital Management US LLC	23,513	$225K	0.0%	N/A	0.044%
2/18/2026	Quadrature Capital Ltd	31,090	$297K	0.0%	+14.2%	0.058%
2/18/2026	Man Group plc	269,513	$2.57M	0.0%	+104.2%	0.501%
2/18/2026	Armistice Capital LLC	1,500,000	$14.33M	0.2%	-17.8%	2.787%
2/17/2026	ADAR1 Capital Management LLC	1,457,764	$13.92M	1.0%	-0.8%	2.708%
2/17/2026	PDT Partners LLC	11,334	$108K	0.0%	N/A	0.021%
2/17/2026	AQR Capital Management LLC	186,785	$1.78M	0.0%	-12.9%	0.347%
2/17/2026	Trexquant Investment LP	19,384	$185K	0.0%	-93.1%	0.036%
2/17/2026	Jump Financial LLC	237,828	$2.27M	0.0%	+27.7%	0.442%
2/17/2026	Price T Rowe Associates Inc. MD	81,515	$779K	0.0%	+3.8%	0.151%
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2/17/2026	Monimus Capital Management LP	254,122	$2.43M	1.6%	-1.5%	0.472%
2/17/2026	Diadema Partners LP	106,539	$1.02M	0.2%	N/A	0.198%
2/17/2026	Russell Investments Group Ltd.	99,350	$949K	0.0%	-22.2%	0.185%
2/17/2026	Atom Investors LP	17,026	$163K	0.0%	-20.1%	0.032%
2/17/2026	ExodusPoint Capital Management LP	87,990	$840K	0.0%	+190.8%	0.163%
2/17/2026	Royal Bank of Canada	4,427	$42K	0.0%	-57.1%	0.008%
2/17/2026	Graham Capital Management L.P.	27,756	$265K	0.0%	-48.0%	0.052%
2/17/2026	Persistent Asset Partners Ltd	28,589	$273K	0.1%	N/A	0.053%
2/16/2026	Squarepoint Ops LLC	218,041	$2.08M	0.0%	+71.6%	0.405%
2/16/2026	Mariner LLC	577,938	$5.52M	0.0%	-2.2%	1.074%
2/16/2026	Entropy Technologies LP	16,900	$161K	0.0%	N/A	0.031%
2/16/2026	Barclays PLC	183,625	$1.75M	0.0%	+87.2%	0.341%
2/13/2026	Marshall Wace LLP	54,778	$523K	0.0%	N/A	0.102%
2/13/2026	Rubric Capital Management LP	3,677,331	$35.12M	0.4%	+138.7%	6.831%
2/13/2026	Jacobs Levy Equity Management Inc.	978,011	$9.34M	0.0%	+11.6%	1.817%
2/13/2026	Rafferty Asset Management LLC	82,553	$788K	0.0%	N/A	0.153%
2/13/2026	Headlands Technologies LLC	23,352	$223K	0.0%	N/A	0.043%
2/13/2026	Birchview Capital LP	441,019	$4.21M	2.5%	-19.7%	0.819%
2/13/2026	Charles Schwab Investment Management Inc.	357,335	$3.41M	0.0%	+1.9%	0.664%
2/13/2026	State Street Corp	2,267,802	$21.66M	0.0%	+151.7%	4.213%
2/13/2026	Martingale Asset Management L P	63,453	$606K	0.0%	N/A	0.118%
2/13/2026	Wells Fargo & Company MN	60,108	$574K	0.0%	+48.7%	0.112%
2/12/2026	DRW Securities LLC	11,955	$114K	0.0%	N/A	0.022%
2/12/2026	MetLife Investment Management LLC	25,501	$244K	0.0%	+31.7%	0.047%
2/12/2026	Renaissance Technologies LLC	435,515	$4.16M	0.0%	+17.3%	0.809%
2/12/2026	Dimensional Fund Advisors LP	775,207	$7.40M	0.0%	-3.9%	1.440%
2/12/2026	Federated Hermes Inc.	974,367	$9.31M	0.0%	+40.6%	1.810%
2/12/2026	Campbell & CO Investment Adviser LLC	94,155	$899K	0.0%	N/A	0.175%
2/12/2026	Nuveen LLC	759,107	$7.25M	0.0%	+13.6%	1.410%
2/11/2026	DCF Advisers LLC	195,747	$1.87M	0.5%	-2.5%	0.364%
2/11/2026	Deutsche Bank AG	35,482	$339K	0.0%	+5.1%	0.066%
2/11/2026	Fox Run Management L.L.C.	10,045	$96K	0.0%	-77.3%	0.019%
2/11/2026	Franklin Resources Inc.	47,251	$451K	0.0%	-22.8%	0.088%
2/11/2026	Los Angeles Capital Management LLC	95,406	$1M	0.0%	-20.1%	0.177%
2/10/2026	Goldman Sachs Group Inc.	935,333	$8.93M	0.0%	+164.8%	1.738%
2/10/2026	Intech Investment Management LLC	20,601	$197K	0.0%	+6.3%	0.038%
2/9/2026	Geode Capital Management LLC	1,063,069	$10.15M	0.0%	+4.3%	1.975%
2/6/2026	Covestor Ltd	21,793	$208K	0.1%	-30.7%	0.040%
2/6/2026	PNC Financial Services Group Inc.	28,128	$269K	0.0%	+55.1%	0.052%
2/6/2026	ProShare Advisors LLC	10,425	$100K	0.0%	N/A	0.019%
2/5/2026	Duncan Williams Asset Management LLC	70,281	$625K	0.2%	-20.4%	0.131%
2/5/2026	Pinnacle Associates Ltd.	62,724	$599K	0.0%	-12.0%	0.117%
2/2/2026	Strs Ohio	17,600	$168K	0.0%	-38.9%	0.033%
1/29/2026	UBS Group AG	426,360	$4.07M	0.0%	+6.4%	0.792%
1/29/2026	Focused Wealth Management Inc	107,479	$1.03M	0.1%	+88.1%	0.200%
1/22/2026	Massachusetts Financial Services Co. MA	45,970	$439K	0.0%	-3.2%	0.085%
1/14/2026	Hennion & Walsh Asset Management Inc.	91,284	$872K	0.0%	+7.9%	0.170%
1/9/2026	SG Americas Securities LLC	63,018	$602K	0.0%	+11.1%	0.117%
1/9/2026	Assenagon Asset Management S.A.	76,769	$733K	0.0%	-14.4%	0.143%
1/1/2026	JPMorgan Chase & Co.	735,765	$7.18M	0.0%	+479.6%	1.367%
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11/17/2025	Jacobs Levy Equity Management Inc.	876,528	$8.56M	0.0%	+26.5%	1.628%
11/17/2025	Armistice Capital LLC	1,824,000	$17.80M	0.3%	-18.4%	3.388%
11/17/2025	Proficio Capital Partners LLC	30,136	$294K	0.0%	N/A	0.056%
11/17/2025	Qube Research & Technologies Ltd	254,245	$2.48M	0.0%	-38.7%	0.472%
11/17/2025	Palo Alto Investors LP	1,324,028	$12.92M	2.4%	+3.9%	2.460%
11/17/2025	Mariner LLC	590,897	$5.77M	0.0%	+52.8%	1.098%
11/17/2025	Millennium Management LLC	621,099	$6.06M	0.0%	+264.1%	1.154%
11/17/2025	MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd.	18,834	$184K	0.0%	-11.2%	0.035%
11/17/2025	Jain Global LLC	11,780	$115K	0.0%	-35.5%	0.022%
11/17/2025	Bank of America Corp DE	277,096	$2.70M	0.0%	+31.4%	0.515%

PRTA Institutional Ownership - Frequently Asked Questions

During the previous two years, 156 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 130 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 14,109,831 shares in the last 24 months. This purchase volume represents approximately $136.40M in transactions.

Of the 46 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), Dimensional Fund Advisors LP ($187.13K), and Qube Research & Technologies Ltd ($160.58K).

Institutional investors have sold a total of 4,915,708 shares in the last 24 months. This volume of shares sold represents approximately $47.76M 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 8/24/2026. New 13F filings are added each quarter as they're published.

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Prothena (PRTA) Institutional Ownership

PRTA Institutional Buying and Selling by Quarter

Prothena Major Shareholders & Ownership History

PRTA Institutional Ownership - Frequently Asked Questions

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Prothena (PRTA) Institutional Ownership

Institutional Ownership Changes (13F Filings) for Prothena (NASDAQ:PRTA)

PRTA Institutional Buying and Selling by Quarter

Prothena Major Shareholders & Ownership History

PRTA Institutional Ownership - Frequently Asked Questions

Who are the largest shareholders of PRTA shares?

What percentage of Prothena's stock is owned by institutional investors?

Which institutional investors have been buying Prothena's stock?

How much institutional buying is happening at Prothena?

Which of Prothena's major shareholders have been selling company stock?

How much institutional selling is happening at Prothena?

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