Prothena Corp Public PRTA Institutional Ownership

NASDAQ PRTA

$8.03 -0.47 (-5.53%)

At close: Oct 21, 2026 · 4:00 PM EDT

Institutions by Trading Activity

188 Institutions

Increased 84 44.7%

Unchanged 46 24.5%

Reduced 58 30.9%

Ownership Statistics

13F · as of 30 Jun, 2026

Institutional Ownership

90.48%

▲+2.42 pp QoQ

Shares Held by Institutions

47.18Mn

of 52.15Mn outstanding

▼-0.25% QoQ

Shares Outstanding

52.15Mn

4.96Mn held outside 13F filers

Institutional Investors

188

filed 13F for Jun 2026

▲+2 vs prior quarter

Net Shares Added (QoQ)

-116.86K

distributed since last quarter

Value of Holdings

$401.04Mn

reported market value

Shares Owned by Institutions

Shares held % of outstanding

Latest —

Average ownership —

Peak ownership —

Shares Purchased/Sold by Institutions

Accumulated Distributed

Latest quarter —

Net over range —

Accumulating quarters —

Ownership Summary

Updated Oct 11, 2026

Prothena Corp Public Ltd Co (NASDAQ:PRTA) appeared in the 13F filings of 188 institutional investors for the quarter ended June 30, 2026.

Collectively, these holders controlled 90.48% of Prothena Corp Public's outstanding shares in Q2 2026, up from 88.07% in Q1 2026.
Total shares held in Prothena Corp Public fell 0.25% from Q1 2026, while the number of holders rose 1.08% from Q2 2025.
Of these 188 holders, 84 added to their positions, 58 reduced their stakes and 46 left their positions unchanged.
Institutional investors held 47.18Mn shares of Prothena Corp Public in total at the end of Q2 2026, down 116.86K from the prior quarter and up 7.51Mn from a year earlier.
FMR LLC held the largest position in PRTA at 7.2Mn shares as of June 30, 2026, or 13.81% of shares outstanding.
The biggest increases in PRTA positions during Q2 2026 came from Acadian Asset Management LLC (+463.05K shares), State Street Corp (+454.93K shares), Man Group plc (+296.54K shares), BlackRock, Inc. (+223.79K shares) and Vanguard Portfolio Management LLC (+205.31K shares).
Holders that trimmed the most shares of Prothena Corp Public in Q2 2026 while keeping a position were FMR LLC (-352K shares), Morgan Stanley (-235.1K shares), Nuveen, LLC (-202.21K shares), Bank of America Corp (-185.39K shares) and Monimus Capital Management, LP (-156.56K shares).
Per Business Quant, the top 10 investors in PRTA for the quarter ended June 30, 2026 were FMR LLC (7.2Mn shares), Rubric Capital Management LP (5Mn shares), BlackRock, Inc. (4.87Mn shares), State Street Corp (2.39Mn shares), Acadian Asset Management LLC (2.01Mn shares), Vanguard Portfolio Management LLC (1.65Mn shares), D. E. Shaw & Co., Inc. (1.61Mn shares), ADAR1 Capital Management, LLC (1.55Mn shares), Two Sigma Investments, LP (1.26Mn shares) and Palo Alto Investors LP (1.14Mn shares).

Form 13F Holdings

188 Institutional Holders

Report period 30 Jun, 2026

Total shares held 47.18Mn

Of outstanding 90.48%

#	Institution	CIK	Shares Held	% of Outstanding	Change (QoQ)	Change (%)	Value (USD)
1	FMR LLC	0000315066	7,199,218	13.81%	▼352,000	-4.66%	$70.48Mn
2	Rubric Capital Management LP	0001687509	5,000,000	9.59%	0	0.00%	$48.95Mn
3	BlackRock, Inc.	0002012383	4,867,955	9.34%	▲223,795	+4.82%	$47.66Mn
4	State Street Corp	0000093751	2,393,424	4.59%	▲454,926	+23.47%	$23.43Mn
5	ACADIAN ASSET MANAGEMENT LLC	0000916542	2,010,645	3.86%	▲463,052	+29.92%	$19.68K
6	VANGUARD PORTFOLIO MANAGEMENT LLC	0002100121	1,651,293	3.17%	▲205,314	+14.20%	$16.17Mn
7	D. E. Shaw & Co., Inc.	0001009207	1,611,457	3.09%	▼151,890	-8.61%	$15.78Mn
8	ADAR1 Capital Management, LLC	0001940272	1,554,535	2.98%	▼26,908	-1.70%	$15.22Mn
9	TWO SIGMA INVESTMENTS, LP	0001179392	1,264,987	2.43%	▲59,009	+4.89%	$12.38Mn
10	Palo Alto Investors LP	0001306923	1,143,155	2.19%	▼65,413	-5.41%	$11.19Mn
11	GEODE CAPITAL MANAGEMENT, LLC	0001214717	1,125,877	2.16%	▲27,711	+2.52%	$11.02Mn
12	Federated Hermes, Inc.	0001056288	1,084,401	2.08%	▲24,552	+2.32%	$10.62Mn
13	Morgan Stanley	0000895421	995,348	1.91%	▼235,100	-19.11%	$9.74Mn
14	Goldman Sachs Group Inc	0000886982	979,730	1.88%	▲160,845	+19.64%	$9.59Mn
15	JACOBS LEVY EQUITY MANAGEMENT, INC	0000884414	965,988	1.85%	▼6,029	-0.62%	$9.46Mn
16	DIMENSIONAL FUND ADVISORS LP	0000354204	905,651	1.74%	▲123,048	+15.72%	$8.87Mn
17	Qube Research & Technologies Ltd	0001729829	791,169	1.52%	▲176,566	+28.73%	$7.75Mn
18	RENAISSANCE TECHNOLOGIES LLC	0001037389	697,615	1.34%	▲90,100	+14.83%	$6.83Mn
19	Man Group plc	0001637460	678,116	1.30%	▲296,542	+77.72%	$6.64Mn
20	Mariner, LLC	0001373442	625,095	1.20%	▲62,013	+11.01%	$6.12Mn

Showing 1 to 20 of 188 holders