ADAR1 Capital Management’s Prothena Corp PRTA Stock Holding History

ADAR1 Capital Management’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
2026 Q2	$15.2M	Sell	1,554,535 -26,908	-2%	-$266K	0.7%	32
2026 Q1	$15.4M	Buy	1,581,443 +123,679	+8%	+$1.13M	0.9%	22
2025 Q4	$13.9M	Sell	1,457,764 -11,334	-0.8%	-$115K	1.02%	22
2025 Q3	$14.3M	Sell	1,469,098 -1,905,911	-56%	-$14.6M	1.35%	13
2025 Q2	$20.5M	Buy	+3,375,009	New	+$25.3M	3.14%	8
2024 Q3	–	Sell	-5,988	Closed	-$124K	–	327
2024 Q2	$124K	Hold	5,988	–	–	0.02%	161
2024 Q1	$148K	Sell	5,988 -114	-2%	-$3.39K	0.03%	133
2023 Q4	$222K	Buy	+6,102	New	+$235K	0.08%	82

Other funds holding PRTA

Fidelity Investments Boston, Massachusetts $2.3T AUM 54.33% 1-Year Est. Return

RCMNY

Rubric Capital Management (New York) New York $10.9B AUM 70.31% 1-Year Est. Return

BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return

State Street Boston, Massachusetts $3.37T AUM 44.26% 1-Year Est. Return

Acadian Asset Management Boston, Massachusetts $84.2B AUM 55.88% 1-Year Est. Return

Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM

D.E. Shaw & Co New York $210B AUM 57.28% 1-Year Est. Return

Two Sigma Investments New York $138B AUM 41.87% 1-Year Est. Return

PAI

Palo Alto Investors Palo Alto, California $724M AUM 96.91% 1-Year Est. Return

Geode Capital Management Boston, Massachusetts $1.88T AUM 44.46% 1-Year Est. Return

ADAR1 Capital Management's PRTA Position: Q2 2026 in Review

ADAR1 Capital Management reduced its Prothena Corp (PRTA) stake by 1.7% in Q2 2026, selling an estimated $266K and leaving 1,554,535 shares worth $15.2M. The position accounts for 0.7% of the portfolio, ranked #32.

ADAR1 Capital Management first reported a position in PRTA in Q4 2023 and has held it in 8 quarters since. The position peaked at $20.5M in Q2 2025. 188 funds tracked by Wall St. Rank hold PRTA as of Q2 2026.

ADAR1 Capital Management held 1,554,535 shares of Prothena Corp worth $15.2M as of Q2 2026.
ADAR1 Capital Management sold 26,908 Prothena Corp shares in Q2 2026, an estimated $266K.
Prothena Corp made up 0.7% of ADAR1 Capital Management's portfolio in Q2 2026, its #32 holding.
ADAR1 Capital Management first reported a position in Prothena Corp in Q4 2023 and has held it in 8 quarters since.
ADAR1 Capital Management's Prothena Corp position peaked at $20.5M in Q2 2025.
188 funds tracked by Wall St. Rank held Prothena Corp as of Q2 2026.

Based on ADAR1 Capital Management's 13F filing for Q2 2026, filed 14 Aug 2026.