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	$484K	Sell	49,800 -51,000	-51%	-$467K	﹤0.01%	9393
2025 Q4	$963K	Sell	100,800 -29,800	-23%	-$303K	﹤0.01%	7478
2025 Q3	$1.27M	Sell	130,600 -28,500	-18%	-$219K	﹤0.01%	7016
2025 Q2	$966K	Buy	159,100 +130,300	+452%	+$978K	﹤0.01%	7180
2025 Q1	$356K	Sell	28,800 -4,800	-14%	-$67.9K	﹤0.01%	9213
2024 Q4	$465K	Buy	33,600 +12,700	+61%	+$200K	﹤0.01%	8719
2024 Q3	$350K	Buy	20,900 +4,200	+25%	+$90.3K	﹤0.01%	9005
2024 Q2	$345K	Sell	16,700 -6,100	-27%	-$132K	﹤0.01%	8865
2024 Q1	$565K	Sell	22,800 -11,300	-33%	-$336K	﹤0.01%	8114
2023 Q4	$1.24M	Buy	34,100 +3,900	+13%	+$150K	﹤0.01%	6267
2023 Q3	$1.46M	Buy	30,200 +5,800	+24%	+$345K	﹤0.01%	5827
2023 Q2	$1.67M	Buy	24,400 +5,600	+30%	+$361K	﹤0.01%	5482
2023 Q1	$911K	Sell	18,800 -8,500	-31%	-$449K	﹤0.01%	6982
2022 Q4	$1.64M	Sell	27,300 -95,300	-78%	-$5.58M	﹤0.01%	5853
2022 Q3	$7.43M	Buy	122,600 +77,300	+171%	+$2.44M	﹤0.01%	3208
2022 Q2	$1.23M	Buy	45,300 +600	+1%	+$17.6K	﹤0.01%	6543
2022 Q1	$1.64M	Buy	44,700 +27,200	+155%	+$980K	﹤0.01%	6537
2021 Q4	$865K	Sell	17,500 -1,100	-6%	-$61K	﹤0.01%	8303
2021 Q3	$1.32M	Sell	18,600 -5,300	-22%	-$329K	﹤0.01%	7410
2021 Q2	$1.23M	Sell	23,900 -14,700	-38%	-$459K	﹤0.01%	7794
2021 Q1	$970K	Buy	38,600 +22,000	+133%	+$414K	﹤0.01%	8193
2020 Q4	$199K	Buy	+16,600	New	+$196K	﹤0.01%	9734
2020 Q2	–	Sell	-21,000	Closed	-$225K	–	10350
2020 Q1	$225K	Sell	21,000 -2,900	-12%	-$35.1K	﹤0.01%	7818
2019 Q4	$378K	Buy	+23,900	New	+$256K	﹤0.01%	7242
2019 Q1	–	Sell	-19,300	Closed	-$199K	–	9734
2018 Q4	$199K	Sell	19,300 -12,000	-38%	-$143K	﹤0.01%	7866
2018 Q3	$409K	Buy	31,300 +4,900	+19%	+$70.8K	﹤0.01%	7025
2018 Q2	$385K	Sell	26,400 -39,900	-60%	-$788K	﹤0.01%	6799
2018 Q1	$2.43M	Buy	66,300 +59,100	+821%	+$2.15M	﹤0.01%	3435
2017 Q4	$270K	Sell	7,200 -1,100	-13%	-$56K	﹤0.01%	6631
2017 Q3	$538K	Buy	8,300 +400	+5%	+$24.5K	﹤0.01%	5217
2017 Q2	$428K	Sell	7,900 -1,300	-14%	-$69.3K	﹤0.01%	5341
2017 Q1	$513K	Buy	9,200 +1,800	+24%	+$94.6K	﹤0.01%	4974
2016 Q4	$364K	Sell	7,400 -2,300	-24%	-$127K	﹤0.01%	5398
2016 Q3	$582K	Sell	9,700 -12,900	-57%	-$692K	﹤0.01%	4616
2016 Q2	$790K	Buy	22,600 +8,100	+56%	+$353K	﹤0.01%	3874
2016 Q1	$597K	Sell	14,500 -1,300	-8%	-$50.9K	﹤0.01%	4156
2015 Q4	$1.08M	Buy	15,800 +10,600	+204%	+$639K	﹤0.01%	3471
2015 Q3	$236K	Sell	5,200 -6,100	-54%	-$355K	﹤0.01%	5918
2015 Q2	$595K	Sell	11,300 -2,500	-18%	-$98.7K	﹤0.01%	4698
2015 Q1	$526K	Buy	+13,800	New	+$354K	﹤0.01%	4822
2014 Q4	–	Sell	-2,700	Closed	-$60K	–	8680
2014 Q3	$60K	Sell	2,700 -2,200	-45%	-$46.6K	﹤0.01%	6789
2014 Q2	$110K	Buy	+4,900	New	+$123K	﹤0.01%	6159

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.