Prothena Corporation plc

PRTA

Held by 2 specialist biotech funds

High short interest · No specialist buying

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Fund Holdings

EcoR1 Capital

Rock Springs Capital

Position history (shares)

Rock Springs Capital

3Q

3 quarters

Position Trend

May 15, 2025

$149.5M

2 funds

Aug 14, 2025

$3.0M

1 fund

Nov 14, 2025

$248K

1 fund

Feb 17, 2026

$0

0 funds

-100% total institutional value over 4 quarters

Short Interest

High short interest

Short Shares

7.04M

Change

-0.5%

Days to Cover

13.4

% of Float

15.6%

Settlement

Mar 13, 2026

Short interest over 2 periods

Catalysts

No catalysts tracked.

Activist Filings

SC 13G/AOrbiMed Advisors3.7%Feb 12, 2021

SC 13GOrbiMed Advisors5.7%Feb 14, 2020

Position Details

EcoR1 CapitalEXITFeb 17, 2026

Shares: 0Value: N/A

Rock Springs CapitalEXITFeb 17, 2026

Shares: 25,398Value: $248K

+ 6more — see how much conviction went in

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Insider Signals

No insider signals tracked.

Also Held by These Funds

APLS2 funds IMNM2 funds JANX2 funds JAZZ2 funds MDGL2 funds BBIO2 funds TNGX2 funds CNTA2 funds

Research Links

Yahoo Finance →SEC EDGAR →ClinicalTrials.gov →

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