Massachusetts Financial Services
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Massachusetts Financial Services’s Prothena Corp PRTA Stock Holding History

Massachusetts Financial Services’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 		$1.24M Sell
126,990
-5,061
-4% -$50K ﹤0.01% 876
2026
Q1 		$1.28M Buy
132,051
+86,081
+187% +$789K ﹤0.01% 830
2025
Q4 		$439K Sell
45,970
-1,519
-3% -$15.5K ﹤0.01% 879
2025
Q3 		$463K Buy
47,489
+3,125
+7% +$24K ﹤0.01% 833
2025
Q2 		$269K Buy
44,364
+548
+1% +$4.11K ﹤0.01% 864
2025
Q1 		$542K Sell
43,816
-999
-2% -$14.1K ﹤0.01% 845
2024
Q4 		$621K Buy
+44,815
New +$707K ﹤0.01% 837
2022
Q2 		– Sell
-13,556
Closed -$496K – 877
2022
Q1 		$496K Sell
13,556
-28,302
-68% -$1.02M ﹤0.01% 823
2021
Q4 		$2.07M Sell
41,858
-848
-2% -$47K ﹤0.01% 777
2021
Q3 		$3.04M Sell
42,706
-562
-1% -$34.9K ﹤0.01% 741
2021
Q2 		$2.22M Sell
43,268
-30,071
-41% -$938K ﹤0.01% 768
2021
Q1 		$1.84M Sell
73,339
-35,255
-32% -$663K ﹤0.01% 778
2020
Q4 		$1.3M Buy
108,594
+21,373
+25% +$253K ﹤0.01% 778
2020
Q3 		$871K Buy
+87,221
New +$1.05M ﹤0.01% 786

Other funds holding PRTA

Fidelity Investments
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
BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
State Street
State Street Boston, Massachusetts $3.37T AUM 44.26% 1-Year Est. Return
Acadian Asset Management
Acadian Asset Management Boston, Massachusetts $84.2B AUM 55.88% 1-Year Est. Return
Vanguard Portfolio Management
Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM
D.E. Shaw & Co
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
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

Massachusetts Financial Services's PRTA Position: Q2 2026 in Review

Massachusetts Financial Services reduced its Prothena Corp (PRTA) stake by 3.8% in Q2 2026, selling an estimated $50K and leaving 126,990 shares worth $1.24M. The position accounts for ﹤0.01% of the portfolio, ranked #876.

Massachusetts Financial Services first reported a position in PRTA in Q3 2020 and has held it in 14 quarters since. The position peaked at $3.04M in Q3 2021. 188 funds tracked by Wall St. Rank hold PRTA as of Q2 2026.

  • Massachusetts Financial Services held 126,990 shares of Prothena Corp worth $1.24M as of Q2 2026.
  • Massachusetts Financial Services sold 5,061 Prothena Corp shares in Q2 2026, an estimated $50K.
  • Prothena Corp made up ﹤0.01% of Massachusetts Financial Services's portfolio in Q2 2026, its #876 holding.
  • Massachusetts Financial Services first reported a position in Prothena Corp in Q3 2020 and has held it in 14 quarters since.
  • Massachusetts Financial Services's Prothena Corp position peaked at $3.04M in Q3 2021.
  • 188 funds tracked by Wall St. Rank held Prothena Corp as of Q2 2026.

Based on Massachusetts Financial Services's 13F filing for Q2 2026, filed 3 Aug 2026.