Question 1

Does Simplex Trading own PRTA stock?

Accepted Answer

Yes. As of its Q3 2026 13F, Simplex Trading holds 1,352 shares of PRTA (Prothena), worth $11,329.

Question 2

How many shares of PRTA does Simplex Trading own?

Accepted Answer

As of its Q3 2026 13F, Simplex Trading holds 1,352 shares of PRTA (Prothena).

Question 3

What is Simplex Trading's PRTA position worth?

Accepted Answer

As of its Q3 2026 13F, Simplex Trading's PRTA position is worth $11,329.

Question 4

Is Simplex Trading buying or selling PRTA?

Accepted Answer

In Q3 2026, Simplex Trading opened a new PRTA position of 1,352 shares.

Question 5

When did Simplex Trading first buy PRTA?

Accepted Answer

Simplex Trading already held PRTA in its Q1 2019 13F, the earliest on record, and has listed it in 21 quarterly 13F filings.

Quarter	Action	Shares	Change	Value	Weight	Price	Conviction
2026-Q3 Latest	New	1,352	—	$11,329	0.0%	$8.38	27
2026-Q2	Exited	0	-100.0%	$0	0.0%	$9.79	0
2026-Q1	Decreased	1,303	-32.4%	$12,665	0.0%	$9.72	0
2025-Q4	Decreased	1,927	-95.4%	$18,402	0.0%	$9.55	0
2025-Q3	Decreased	42,044	-2.8%	$410,000	0.0%	$9.76	0
2025-Q2	New	43,264	—	$262,000	0.0%	$6.07	32
2024-Q4	Exited	0	-100.0%	$0	0.0%	$13.85	0
2024-Q3	Increased	5,977	+163.7%	$99,000	0.0%	$16.73	35