SEI Investments’s Prothena Corp PRTA Stock Holding History

SEI Investments’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	$302K	Buy	30,877 +13,629	+79%	+$135K	﹤0.01%	2861
2026 Q1	$168K	Buy	+17,248	New	+$158K	﹤0.01%	3006
2023 Q4	–	Sell	-4,717	Closed	-$228K	–	2666
2023 Q3	$228K	Sell	4,717 -2,385	-34%	-$142K	﹤0.01%	2405
2023 Q2	$485K	Buy	7,102 +1,091	+18%	+$70.4K	﹤0.01%	2141
2023 Q1	$291K	Buy	+6,011	New	+$318K	﹤0.01%	2349
2018 Q1	–	Sell	-5,030	Closed	-$189K	–	3621
2017 Q4	$189K	Buy	5,030 +1,770	+54%	+$90.1K	﹤0.01%	1943
2017 Q3	$211K	Hold	3,260	–	–	﹤0.01%	1860
2017 Q2	$176K	Buy	+3,260	New	+$174K	﹤0.01%	1904

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

ACM

ADAR1 Capital Management Austin, Texas $2.19B AUM 374.99% 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

SEI Investments's PRTA Position: Q2 2026 in Review

SEI Investments increased its Prothena Corp (PRTA) stake by 79% in Q2 2026, buying an estimated $135K and bringing the position to 30,877 shares worth $302K. The position accounts for ﹤0.01% of the portfolio, ranked #2861.

SEI Investments first reported a position in PRTA in Q2 2017 and has held it in 8 quarters since. The position peaked at $485K in Q2 2023. 188 funds tracked by Wall St. Rank hold PRTA as of Q2 2026.

SEI Investments held 30,877 shares of Prothena Corp worth $302K as of Q2 2026.
SEI Investments bought 13,629 Prothena Corp shares in Q2 2026, an estimated $135K.
Prothena Corp made up ﹤0.01% of SEI Investments's portfolio in Q2 2026, its #2861 holding.
SEI Investments first reported a position in Prothena Corp in Q2 2017 and has held it in 8 quarters since.
SEI Investments's Prothena Corp position peaked at $485K in Q2 2023.
188 funds tracked by Wall St. Rank held Prothena Corp as of Q2 2026.

Based on SEI Investments's 13F filing for Q2 2026, filed 14 Aug 2026.