Citadel Advisors’s Prothena Corp PRTA Stock Holding History

Citadel Advisors’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 Q1	$850K	Buy	87,400 +24,300	+39%	+$223K	﹤0.01%	8032
2025 Q4	$603K	Sell	63,100 -10,900	-15%	-$111K	﹤0.01%	8585
2025 Q3	$722K	Buy	74,000 +10,500	+17%	+$80.7K	﹤0.01%	8269
2025 Q2	$385K	Buy	63,500 +39,200	+161%	+$294K	﹤0.01%	9233
2025 Q1	$301K	Sell	24,300 -82,800	-77%	-$1.17M	﹤0.01%	9586
2024 Q4	$1.48M	Buy	107,100 +75,300	+237%	+$1.19M	﹤0.01%	6256
2024 Q3	$532K	Buy	31,800 +4,900	+18%	+$105K	﹤0.01%	8127
2024 Q2	$555K	Buy	26,900 +2,900	+12%	+$62.8K	﹤0.01%	7842
2024 Q1	$594K	Sell	24,000 -100,000	-81%	-$2.97M	﹤0.01%	7993
2023 Q4	$4.51M	Buy	124,000 +112,400	+969%	+$4.33M	﹤0.01%	3948
2023 Q3	$560K	Sell	11,600 -5,900	-34%	-$351K	﹤0.01%	7817
2023 Q2	$1.19M	Buy	17,500 +11,300	+182%	+$729K	﹤0.01%	6091
2023 Q1	$301K	Sell	6,200 -6,800	-52%	-$359K	﹤0.01%	9380
2022 Q4	$783K	Sell	13,000 -25,900	-67%	-$1.52M	﹤0.01%	7297
2022 Q3	$2.36M	Buy	+38,900	New	+$1.23M	﹤0.01%	5277
2022 Q2	–	Sell	-12,000	Closed	-$439K	–	13839
2022 Q1	$439K	Sell	12,000 -3,800	-24%	-$137K	﹤0.01%	9698
2021 Q4	$781K	Sell	15,800 -8,400	-35%	-$466K	﹤0.01%	8557
2021 Q3	$1.72M	Sell	24,200 -18,200	-43%	-$1.13M	﹤0.01%	6741
2021 Q2	$2.18M	Buy	42,400 +8,000	+23%	+$250K	﹤0.01%	6381
2021 Q1	$864K	Buy	34,400 +12,600	+58%	+$237K	﹤0.01%	8468
2020 Q4	$262K	Buy	+21,800	New	+$258K	﹤0.01%	9300
2020 Q3	–	Sell	-10,000	Closed	-$105K	–	10600
2020 Q2	$105K	Sell	10,000 -5,900	-37%	-$65.6K	﹤0.01%	8965
2020 Q1	$170K	Buy	+15,900	New	+$193K	﹤0.01%	8172
2019 Q3	–	Sell	-12,200	Closed	-$129K	–	9634
2019 Q2	$129K	Sell	12,200 -1,300	-10%	-$13.4K	﹤0.01%	8426
2019 Q1	$164K	Sell	13,500 -25,500	-65%	-$318K	﹤0.01%	8340
2018 Q4	$402K	Buy	39,000 +5,600	+17%	+$66.6K	﹤0.01%	6759
2018 Q3	$437K	Buy	33,400 +7,900	+31%	+$114K	﹤0.01%	6915
2018 Q2	$372K	Sell	25,500 -1,200	-4%	-$23.7K	﹤0.01%	6860
2018 Q1	$980K	Buy	26,700 +12,300	+85%	+$447K	﹤0.01%	4837
2017 Q4	$540K	Buy	14,400 +11,200	+350%	+$570K	﹤0.01%	5535
2017 Q3	$207K	Sell	3,200 -4,000	-56%	-$245K	﹤0.01%	6645
2017 Q2	$390K	Buy	+7,200	New	+$384K	﹤0.01%	5489
2016 Q4	–	Sell	-10,800	Closed	-$648K	–	7713
2016 Q3	$648K	Buy	+10,800	New	+$579K	﹤0.01%	4452
2016 Q2	–	Sell	-7,600	Closed	-$313K	–	7269
2016 Q1	$313K	Buy	7,600 +1,000	+15%	+$39.1K	﹤0.01%	5047
2015 Q4	$450K	Buy	6,600 +300	+5%	+$18.1K	﹤0.01%	4602
2015 Q3	$286K	Buy	6,300 +2,500	+66%	+$146K	﹤0.01%	5637
2015 Q2	$200K	Sell	3,800 -6,900	-64%	-$272K	﹤0.01%	6323
2015 Q1	$408K	Buy	+10,700	New	+$274K	﹤0.01%	5227
2014 Q4	–	Sell	-12,200	Closed	-$270K	–	8682
2014 Q3	$270K	Buy	12,200 +1,700	+16%	+$36K	﹤0.01%	5395
2014 Q2	$237K	Buy	+10,500	New	+$263K	﹤0.01%	5372

Other funds holding PRTA

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

RCMNY

Rubric Capital Management (New York) New York $9.44B AUM 68.42% 1-Year Est. Return

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

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

D.E. Shaw & Co New York $166B AUM 43.98% 1-Year Est. Return

ACM

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

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

VPM

Vanguard Portfolio Management Malvern, Pennsylvania $1.91T AUM

Morgan Stanley New York $1.66T AUM 25.57% 1-Year Est. Return

PAI

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

Citadel Advisors's PRTA Position: Q1 2026 in Review

Citadel Advisors reduced its Prothena Corp (PRTA) stake by 52% in Q1 2026, selling an estimated $4.37M and leaving 435,574 shares worth $4.23M. The position accounts for ﹤0.01% of the portfolio, ranked #4615.

Citadel Advisors first reported a position in PRTA in Q2 2014 and has held it in 42 quarters since. The position peaked at $37.4M in Q3 2015. 185 funds tracked by Wall St. Rank hold PRTA as of Q1 2026.

Citadel Advisors held 435,574 shares of Prothena Corp worth $4.23M as of Q1 2026.
Citadel Advisors sold 476,808 Prothena Corp shares in Q1 2026, an estimated $4.37M.
Prothena Corp made up ﹤0.01% of Citadel Advisors's portfolio in Q1 2026, its #4615 holding.
Citadel Advisors first reported a position in Prothena Corp in Q2 2014 and has held it in 42 quarters since.
Citadel Advisors's Prothena Corp position peaked at $37.4M in Q3 2015.
185 funds tracked by Wall St. Rank held Prothena Corp as of Q1 2026.

Based on Citadel Advisors's 13F filing for Q1 2026, filed 15 May 2026.