PROTHENA CORP PUBLIC LTD CO - Ordinary Shares, par value $0.01 per share (PRTA)

Q: What does CUSIP G72800108 represent in this 13F holders report?

CUSIP G72800108 is the security identifier for PRTA - PROTHENA CORP PUBLIC LTD CO - Ordinary Shares, par value $0.01 per share used to aggregate holder disclosures.

Q: How many institutions held PRTA - PROTHENA CORP PUBLIC LTD CO - Ordinary Shares, par value $0.01 per share in Q1 2021?

136 institutional investors reported PRTA - PROTHENA CORP PUBLIC LTD CO - Ordinary Shares, par value $0.01 per share for Q1 2021. Use the holders table for investor-level position and value details.

CUSIP: G72800108

Q1 2021 13F Holders as of 31 Mar 2021

Security type / class: Equity / Ordinary Shares, par value $0.01 per share
Total 13F shares: 39,992,237
Total 13F value: $1,004,673,605
Share change: +5,163,518
Put/Call ratio: 25%
SEC-reported price per share: $25.12
Number of holders: 136
Value change: +$172,031,286
Number of buys: 58
Number of sells: 61
Shares outstanding: 53,821,313

Security key

G72800108

Report period

Q1 2021

Institutions

136

Top holders

PRTA full security history Ownership snapshot Full 13F holder table Newer quarter: Q2 2021 Previous quarter: Q4 2020 PROTHENA CORP PUBLIC LTD CO SEC filings PROTHENA CORP PUBLIC LTD CO company facts

Broader feeds

Latest 13F filings Latest 13D/G filings Investors directory

Reporting periods

Holder history for CUSIP G72800108

Newer quarter: Q2 2021 Previous quarter: Q4 2020

Recent filing periods:

Q1 2026 Q4 2025 Q3 2025 Q2 2025 Q1 2025 Q4 2024 Q3 2024 Q2 2024

Ownership snapshot

Top reported holders of PRTA - PROTHENA CORP PUBLIC LTD CO - Ordinary Shares, par value $0.01 per share (13F + 13D/G + 3/4/5)

Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.

Comparable stake leader

EcoR1 Capital, LLC

Disclosed value leader

EcoR1 Capital, LLC

Comparable rows

15/15

Latest evidence

31 Dec 2020

13F Lead comparable stake: 18% Showing 1-6 of 15 holder rows.

Quick read

EcoR1 Capital, LLC leads the comparable SEC ownership view at 18%.

15 of 15 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.

Open SEC evidence Opens EcoR1 Capital, LLC's linked filing trail.

Comparable ownership Top 5

EcoR1 Capital, LLC 18%

BlackRock Finance, Inc. 6.9%

First Light Asset Management, LLC 3.8%

ORBIMED ADVISORS LLC 3.3%

DIMENSIONAL FUND ADVISORS LP 3.2%

Ownership % is shown only when SEC disclosures are safely comparable across share classes.

Detailed SEC evidence table Showing 1-6 of 15 holder rows

Holder	Evidence	Ownership %	Position	12M Net Δ	As of
EcoR1 Capital, LLC	13F Company 13F	18%	$113,214,000 9,426,640 shares	—	31 Dec 2020
BlackRock Finance, Inc.	13F Company 13F	6.9%	$44,351,000 3,692,970 shares	—	31 Dec 2020
First Light Asset Management, LLC	13F Company 13F	3.8%	$24,698,000 2,056,453 shares	—	31 Dec 2020
ORBIMED ADVISORS LLC	13F Company 13F	3.3%	$21,587,000 1,797,458 shares	—	31 Dec 2020
DIMENSIONAL FUND ADVISORS LP	13F Company 13F	3.2%	$20,874,000 1,737,969 shares	—	31 Dec 2020
Palo Alto Investors LP	13F Company 13F	3.1%	$20,319,000 1,691,805 shares	—	31 Dec 2020

How to read this table

Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.

13F holder rows

Institutional holders as of Q1 2021

Investor-level positions for this CUSIP, loaded as an interactive table.

Institutions

136

39,992,237

Rows available

136

Investor	Option	Weight %	Change %	SEC-reported value	* Price	Shares	Share Change	Activity	Report Period

^* SEC-reported price is the security price as of the portfolio date and can indicate the last known price at which the security was still held. The marker flags a reported price that did not pass the local price check.

Compare Q1 2021 vs Q4 2020 Across Filers

Q4 2020 holders

125

Q1 2021 holders

136

Holder diff

Investor	Q4 2020 Shares	Q1 2021 Shares	Share Diff	Share Chg %	Q4 2020 value	Q1 2021 value	Value change	Value Chg %

Trend: ostatnie 8 kwartałów (+ wybrane okresy porównania).

Quarterly Holders Trend

Quarterly Value Trend

Quarterly Shares Trend