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PRTA · Prothena Corp Public Ltd Co

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$9.03 -0.26 (-2.80%) At close · Aug 20
Market Cap
$476.92M
Shares
51.34M

Institutional ownership from SEC Form 13F filings. Investment managers with more than $100 million in U.S. equities must disclose their positions every quarter, within 45 days of quarter-end, so the holdings shown can lag the market by up to a quarter.

Holders: 190
Total Value: $472,921,372
Total Shares: 48,306,587

Institutional Ownership Trend

26 quarters

Holder Concentration

Across 190 13F filers · Δ vs Mar 31, 2026
Top Holder
14.9%
Sep 2023 → Jun 2026 · range 14.9% – 22.7%
−1.0 pts
Top 5
44.4%
Sep 2023 → Jun 2026 · range 38.1% – 61.8%
+0.4 pts
Top 10
59.4%
Sep 2023 → Jun 2026 · range 53.0% – 76.3%
+0.6 pts
HHI
566
Sep 2023 → Jun 2026 · range 514 – 1,010
Broadly held−16

Quarterly Activity

vs Mar 31, 2026
New
29
Increased
58
Decreased
57
Sold Out
25
Unchanged
46
Holder count: +4
Institutional value: +2.5%
Shares held: +1.7%

Top Buyers

vs Mar 31, 2026
Institution Added Now Holds Open

Top Sellers

vs Mar 31, 2026
Institution Sold Now Holds Open

Top New Positions

vs Mar 31, 2026
Institution Acquired Value (USD) Open

Top Sold-Out Positions

vs Mar 31, 2026
Institution Previously Held Last Value (USD) Open
Showing 100 of 194
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Holder Value (USD) % of 13F Shares Open
Key facts CIK 1559053 CUSIP G72800108 13F (30d) 177 filings 174 filers Visit website Investor relations