Prothena Corp Public Ltd Co

PRTA

Exchange: Nasdaq
Industry: Pharmaceutical Preparations
SEC CIK: 0001559053

SEC filings (opens in a new tab)

In the last 90 days, Prothena Corp Public Ltd Co insiders filed 6 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.

Q2 2025 vs. Q1 2025

How the institutions holding Prothena Corp Public Ltd Co changed between Q1 2025 and Q2 2025.

All holders in Q2 2025 All holders in Q1 2025

13F holders of PRTA: Q1 2025 compared with Q2 2025
Measure	Q1 2025	Of which not filed for Q2 2025	Q2 2025	Change
Holders	161	1	189	+29
Shares	52.3M	874	41.8M	−10.5M (−20.2%)
Value	$647.2M	$10.8K	$253.6M	−$393.7M (−60.8%)

1 institution that held it in Q1 2025 haven't filed for Q2 2025 yet. Not filing isn't selling, so the changes leave them out.

New holders (51)

Institutions that held Prothena Corp Public Ltd Co at the end of Q2 2025 but not at the end of Q1 2025.

Institutions new to PRTA in Q2 2025
Institution	Shares	Value	% of portfolio
ADAR1 Capital Management, LLC	3,375,009	$20.5M	3.33%
Acadian Asset Management LLC	1,018,177	$6.18M	0.01%
Rangeley Capital, LLC	715,367	$4.34M	5.47%
Balyasny Asset Management LLC	575,792	$3.50M	0.01%
Trexquant Investment LP	552,826	$3.36M	0.04%
Cubist Systematic Strategies, LLC	501,764	$3.05M	0.03%
Granahan Investment Management Inc	461,082	$2.80M	0.11%
Qube Research & Technologies Ltd	414,828	$2.52M	0.00%
Schonfeld Strategic Advisors LLC	307,341	$1.87M	0.01%
Gsa Capital Partners LLP	210,555	$1.28M	0.09%
Squarepoint Ops LLC	209,249	$1.27M	0.00%
Monimus Capital Management, LP	206,475	$1.25M	1.01%
Ameriprise Financial Inc	151,543	$919.9K	0.00%
Two Sigma Advisers, LP	139,800	$848.6K	0.00%
State of Wisconsin Investment Board	103,996	$631.3K	0.00%
Susquehanna Portfolio Strategies, LLC	71,668	$435.0K	0.01%
Monaco Asset Management SAM	70,000	$424.9K	0.16%
Caption Management, LLC	65,100	$395.2K	0.04%
Quantinno Capital Management LP	59,618	$361.9K	0.00%
Quinn Opportunity Partners LLC	50,000	$303.5K	0.03%
Algert Global LLC	48,150	$292.3K	0.01%
Simplex Trading, LLC	43,264	$262.0K	0.01%
Public Employees Retirement System of Ohio	42,158	$255.9K	0.00%
Engineers Gate Manager LP	40,967	$248.7K	0.00%
Graham Capital Management, L.P.	34,042	$206.6K	0.01%
Group One Trading, L.P.	32,258	$195.8K	0.01%
Tudor Investment Corp Et Al	27,999	$170.0K	0.00%
Sherbrooke Park Advisers LLC	27,221	$165.2K	0.07%
Point72 (DIFC) Ltd	23,946	$145.4K	0.01%
Quadrature Capital Ltd	23,752	$144.4K	0.00%
Nebula Research & Development LLC	22,857	$138.7K	0.01%
Mogy Joel R Investment Counsel Inc	20,750	$126.0K	0.01%
Oppenheimer & Co Inc	18,595	$112.9K	0.00%
Voleon Capital Management LP	18,536	$112.5K	0.01%
Jain Global LLC	18,262	$110.8K	0.00%
Los Angeles Capital Management LLC	16,702	$101.4K	0.00%
STRS Ohio	16,400	$99.5K	0.00%
Jones Financial Companies LLLP	14,000	$85.1K	0.00%
Corton Capital Inc.	13,964	$84.8K	0.10%
Two Sigma Securities, LLC	11,683	$70.9K	0.01%
Coastal Bridge Advisors, LLC	11,433	$69.4K	0.01%
Prospera Financial Services Inc	10,000	$60.7K	0.00%
Brown Brothers Harriman & Co	5,000	$30.4K	0.00%
Walleye Capital LLC	2,058	$12.5K	0.00%
Flagship Wealth Advisors, LLC	1,500	$9.11K	0.00%
BNP PARIBAS ASSET MANAGEMENT Holding S.A.	683	$4.00K	0.00%
Point72 Asia (Singapore) Pte. Ltd.	459	$2.79K	0.00%
Huntington National Bank	324	$1.97K	0.00%
MAI Capital Management	155	$941	0.00%
Steward Partners Investment Advisory, LLC	6	$36	0.00%
Koesten, Hirschmann & Crabtree, INC.	1	$9	0.00%

Sold out (22)

Institutions that held Prothena Corp Public Ltd Co at the end of Q1 2025 and filed for Q2 2025 without it.

Institutions that sold out of PRTA in Q2 2025
Institution	Shares, Q1 2025	Value, Q1 2025
EcoR1 Capital, LLC	11,584,280	$143.4M
Siren, L.L.C.	1,283,555	$15.9M
Boxer Capital Management, LLC	690,000	$8.54M
Finepoint Capital LP	640,071	$7.92M
TD Asset Management Inc	62,694	$775.8K
Rafferty Asset Management, LLC	43,978	$544.2K
Corebridge Financial, Inc.	20,831	$257.8K
HRT Financial LP	14,036	$173.0K
Cresset Asset Management, LLC	13,125	$162.4K
ProShare Advisors LLC	11,632	$143.9K
Amundi	2,014	$22.8K
EverSource Wealth Advisors, LLC	304	$3.76K
Aster Capital Management (DIFC) Ltd	227	$3.59K
Boston Private Wealth LLC	274	$3.39K
Caitong International Asset Management Co., Ltd	238	$2.94K
Massmutual Trust Co FSB	112	$1.39K
Coldstream Capital Management Inc	51	$632
Rothschild Investment LLC	45	$557
Larson Financial Group LLC	42	$520
Parkside Financial Bank & Trust	30	$372
Smartleaf Asset Management LLC	9	$118
Hallmark Capital Management Inc	3	$37

Not filed for Q2 2025 yet (1)

Institutions that held Prothena Corp Public Ltd Co at the end of Q1 2025 and haven't filed a 13F for Q2 2025. Not filing isn't selling, so they aren't counted as sold out.

Institutions holding PRTA in Q1 2025 that haven't filed for Q2 2025
Institution	Shares, Q1 2025	Value, Q1 2025
Lindbrook Capital, LLC	874	$10.8K