Palo Alto Investors LP

Position in PRTA — Prothena Corp Public Ltd Co

CIK 1306923 PALO ALTO, CA

Back to PRTA Full portfolio

Position in PRTA

as of Jun 30, 2026 · filed Aug 19, 2026 Compact

Position Value

$11,191,487

-$555,793 QoQ

Shares Held

1,143,155

-5.4% QoQ

Ownership

2.23%

of shares outstanding

% of Portfolio

1.55%

of 13F equity value

Holder Rank

#10

of 187 holders

Holding Since

Mar 2020

26 quarters on record

Voting authority Sole 100% Shared 0% None 0%

Common Shares in PRTA Over Time

Shares Held

Position Value (USD)

Position in Biotechnology

Healthcare · as of Jun 30, 2026

Palo Alto Investors LP holds $594,195,112 across 39 Biotechnology names. PRTA ranks #17 (1.9% of the industry book) .

#	Ticker	Company	Shares	Value (USD)
1	PTCT	Ptc Therapeutics, Inc.	918,846	$74,950,268
2	ACAD	Acadia Pharmaceuticals Inc	2,864,096	$72,461,628
3	INSM	INSMED Inc	413,980	$44,138,547
4	MIRM	Mirum Pharmaceuticals, Inc.	348,808	$40,834,952
5	ANAB	Anaptysbio, Inc	603,489	$40,735,507
6	BMRN	Biomarin Pharmaceutical Inc	682,777	$39,068,499
7	DYN	Dyne Therapeutics, Inc.	1,647,521	$36,591,441
8	IRON	Disc Medicine, Inc.	416,646	$30,473,488

All Filings in PRTA

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26 filing rows on record

Report Date	Value (USD)	Shares	Change	Type	Discretion	Filed
2026-06-30	$11,191,487	1,143,155	-5.4%	Shares	Sole	2026-08-19
2026-03-31	$11,747,280	1,208,568	-8.5%	Shares	Sole	2026-05-15
2025-12-31	$12,610,870	1,320,510	-0.3%	Shares	Sole	2026-02-17
2025-09-30	$12,922,513	1,324,028	+3.9%	Shares	Sole	2025-11-14
2025-06-30	$7,737,750	1,274,753	-23.2%	Shares	Sole	2025-08-14
2025-03-31	$20,539,208	1,659,734	-4.5%	Shares	Sole	2025-05-15
2024-12-31	$24,070,801	1,737,964	0.0%	Shares	Sole	2025-02-14
2024-09-30	$29,076,137	1,737,964	+4.3%	Shares	Sole	2024-11-14
2024-06-30	$34,394,041	1,666,378	+0.2%	Shares	Sole	2024-08-14
2024-03-31	$41,203,606	1,663,448	+0.2%	Shares	Sole	2024-05-15
2023-12-31	$60,326,471	1,660,057	+0.2%	Shares	Sole	2024-02-15
2023-09-30	$79,972,348	1,657,458	0.0%	Shares	Sole	2023-11-14
2023-06-30	$113,171,232	1,657,458	-0.4%	Shares	Sole	2023-08-14
2023-03-31	$80,643,271	1,663,777	+0.3%	Shares	Sole	2023-05-15
2022-12-31	$99,929,264	1,658,577	+0.5%	Shares	Sole	2023-02-14
2022-09-30	$100,025,979	1,649,777	-1.9%	Shares	Sole	2022-11-14
2022-06-30	$45,652,100	1,681,477	0.0%	Shares	Sole	2022-08-15
2022-03-31	$61,491,613	1,681,477	-0.2%	Shares	Sole	2022-05-16
2021-12-31	$83,252,930	1,685,282	0.0%	Shares	Sole	2022-02-14
2021-09-30	$120,042,636	1,685,282	-2.7%	Shares	Sole	2021-11-15
2021-06-30	$89,015,489	1,731,482	-0.6%	Shares	Sole	2021-08-16
2021-03-31	$43,771,725	1,742,505	+3.0%	Shares	Sole	2021-05-17
2020-12-31	$20,318,578	1,691,805	+27.3%	Shares	Sole	2021-02-16
2020-09-30	$13,274,052	1,328,734	+72.3%	Shares	Sole	2020-11-16
2020-06-30	$8,065,339	771,065	-0.5%	Shares	Sole	2020-08-14
2020-03-31	$8,295,667	775,296	—	Shares	Sole	2020-05-15
No filing history on record for this holder in this stock.