Question 1

Does Two Sigma Investments own PRTA stock?

Accepted Answer

Yes. As of its Q2 2026 13F, Two Sigma Investments holds 1,264,987 shares of PRTA (Prothena), worth $12.4M.

Question 2

How many shares of PRTA does Two Sigma Investments own?

Accepted Answer

As of its Q2 2026 13F, Two Sigma Investments holds 1,264,987 shares of PRTA (Prothena).

Question 3

What is Two Sigma Investments' PRTA position worth?

Accepted Answer

As of its Q2 2026 13F, Two Sigma Investments' PRTA position is worth $12.4M.

Question 4

Is Two Sigma Investments buying or selling PRTA?

Accepted Answer

In Q2 2026, Two Sigma Investments increased its PRTA position by 59,009 shares (+4.9%).

Question 5

When did Two Sigma Investments first buy PRTA?

Accepted Answer

Two Sigma Investments already held PRTA in its Q4 2018 13F, the earliest on record, and has listed it in 29 quarterly 13F filings.

Quarter	Action	Shares	Change	Value	Weight	Price	Conviction
2026-Q2 Latest	Increased	1.3M	+4.9%	$12.4M	0.0%	$9.79	29
2026-Q1	Increased	1.2M	+80.0%	$11.7M	0.0%	$9.72	43
2025-Q4	Increased	670,138	+57.1%	$6.4M	0.0%	$9.55	39
2025-Q3	Increased	426,605	+111.8%	$4.2M	0.0%	$9.76	43
2025-Q2	Increased	201,450	+1156.5%	$1.2M	0.0%	$6.07	41
2025-Q1	Decreased	16,033	-58.2%	$198,408	0.0%	$12.38	0
2024-Q4	Increased	38,394	+265.4%	$531,757	0.0%	$13.85	39
2024-Q3	Decreased	10,507	-85.3%	$175,782	0.0%	$16.73	0