Siren LLC’s Prothena Corp PRTA Stock Holding History

Siren LLC’s Portfolio PRTA Stock Details PRTA Fund Activity

Bought

Maintained

Sold

Quarter	Market Value	Status	Shares	Change in Stake	Trade Value	Portfolio Weight	Portfolio Position
2025 Q2	–	Sell	-1,283,555	Closed	-$15.9M	–	125
2025 Q1	$15.9M	Buy	1,283,555 +183,715	+17%	+$2.6M	0.9%	27
2024 Q4	$15.2M	Hold	1,099,840	–	–	0.67%	38
2024 Q3	$18.4M	Buy	+1,099,840	New	+$23.6M	0.92%	34

Other funds holding PRTA

Fidelity Investments Boston, Massachusetts $1.9T AUM 41.92% 1-Year Est. Return

BlackRock New York $5.72T AUM 30.48% 1-Year Est. Return

ACM

ADAR1 Capital Management Austin, Texas $1.7B AUM 340.85% 1-Year Est. Return

Armistice Capital New York $5.62B AUM 36.06% 1-Year Est. Return

Vanguard Group Malvern, Pennsylvania $6.9T AUM 27.45% 1-Year Est. Return

PAI

Palo Alto Investors Palo Alto, California $654M AUM 77.8% 1-Year Est. Return

Federated Hermes Pittsburgh, Pennsylvania $61.5B AUM 30.7% 1-Year Est. Return

Citadel Advisors Miami, Florida $618B AUM 30.34% 1-Year Est. Return

Acadian Asset Management Boston, Massachusetts $70.5B AUM 36% 1-Year Est. Return

State Street Boston, Massachusetts $2.9T AUM 29.55% 1-Year Est. Return

Siren LLC's PRTA Position: Q2 2025 in Review

Siren LLC sold out of Prothena Corp (PRTA) in Q2 2025, closing a stake of 1,283,555 shares — an estimated $15.9M sold.

Siren LLC first reported a position in PRTA in Q3 2024 and held it in 3 quarters. The position peaked at $18.4M in Q3 2024. 188 funds tracked by Wall St. Rank hold PRTA as of Q2 2025.

Siren LLC reported no remaining Prothena Corp position as of Q2 2025 after selling out during the quarter.
Siren LLC sold 1,283,555 Prothena Corp shares in Q2 2025, an estimated $15.9M.
Siren LLC first reported a position in Prothena Corp in Q3 2024 and held it in 3 quarters.
Siren LLC's Prothena Corp position peaked at $18.4M in Q3 2024.
188 funds tracked by Wall St. Rank held Prothena Corp as of Q2 2025.

Based on Siren LLC's 13F filing for Q2 2025, filed 13 Aug 2025.