Prothena Corporation plc (PRTA) Institutional Ownership & Insider Trading

187 institutions reported holding Prothena Corporation plc shares in 13F filings for the quarter ended 2026-06-30, according to EquiReason's reading of their SEC filings. 19 insider trades on Form 4 since 2025-10-01.

Source: SEC EDGAR filings · figures as of 2026-06-30 · read by EquiReason

PRTAProthena Corporation plcFollow PRTA — free

Biotechnology · Healthcare

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Market cap: 421.0M
P/E TTM: —
Dividend yield: —
52-week: —
Next earnings: 29 Oct, in 5 days

Institutions · all 13F filers

quarter to 30 Jun 2026 · filers in both quarters

187 institutions held 92.2% of the shares. Across filers that reported both quarters, shares held changed +0.7%.

Largest moves, shares (millions)

Institutional flow by quarter

net shares added or trimmed, millions · filers in both quarters

Quarter	Holders	Shares held, M	Change	Increased	New	Decreased	Closed
Jun 26	187	47	+0.7%	53	23	52	18
Mar 26	184	47	+0.1%	61	22	49	20
Dec 25	178	47	+9.5%	62	20	51	24
Sep 25	184	43	+3.6%	51	25	59	32
Jun 25	186	42	-20.3%	50	47	41	19
Mar 25	159	52	-2.3%	36	13	54	24
Dec 24	168	54	+4.5%	55	22	35	24
Sep 24	159	51	-2.0%	42	18	40	15

Prothena Corporation plc — questions

Who owns Prothena Corporation plc stock?: 187 institutions reported Prothena Corporation plc shares in 13F filings for the quarter ended 2026-06-30. The largest: FMR LLC (14.0%), Rubric Capital Management LP (9.7%), BlackRock, Inc. (9.5%).
Are Prothena Corporation plc insiders buying or selling?: 19 insider trades on Form 4 since 2025-10-01; the full list, with dates, people and plan status, is on this page.

Every figure on this page comes from Prothena Corporation plc's own SEC filings — see them on SEC EDGAR. Price data is licensed and shown only inside the product.

How these figures are read: methodology · EquiReason.

Important information. Figures on this page are taken from filings submitted to the U.S. Securities and Exchange Commission (SEC) and processed automatically by EquiReason. They may contain errors, omissions or delays, and EquiReason makes no representation or warranty as to their accuracy, completeness or timeliness. Always verify figures against the original filing on SEC EDGAR before relying on them.

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