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Granahan Investment Management’s Prothena Corp PRTA Stock Holding History

Granahan Investment 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
2025
Q3 		– Sell
-461,082
Closed -$2.8M – 161
2025
Q2 		$2.8M Buy
+461,082
New +$3.46M 0.11% 125
2024
Q4 		– Sell
-312,520
Closed -$5.23M – 199
2024
Q3 		$5.23M Sell
312,520
-23,140
-7% -$498K 0.21% 123
2024
Q2 		$6.93M Buy
335,660
+1,740
+0.5% +$37.7K 0.28% 98
2024
Q1 		$8.27M Sell
333,920
-83,237
-20% -$2.48M 0.29% 97
2023
Q4 		$15.2M Buy
417,157
+69,092
+20% +$2.66M 0.5% 63
2023
Q3 		$16.8M Buy
348,065
+53,008
+18% +$3.15M 0.6% 49
2023
Q2 		$20.1M Buy
295,057
+62,429
+27% +$4.03M 0.62% 50
2023
Q1 		$11.3M Buy
232,628
+32,702
+16% +$1.73M 0.34% 80
2022
Q4 		$12M Buy
199,926
+58,818
+42% +$3.44M 0.37% 77
2022
Q3 		$8.55M Sell
141,108
-18,217
-11% -$576K 0.28% 99
2022
Q2 		$4.33M Buy
159,325
+35,219
+28% +$1.03M 0.15% 126
2022
Q1 		$4.54M Buy
124,106
+33,927
+38% +$1.22M 0.11% 136
2021
Q4 		$4.46M Buy
90,179
+44,875
+99% +$2.49M 0.09% 154
2021
Q3 		$3.23M Buy
+45,304
New +$2.81M 0.06% 173
2015
Q3 		– Sell
-33,894
Closed -$1.78M – 263
2015
Q2 		$1.78M Hold
33,894
– – 0.05% 218
2015
Q1 		$1.29M Hold
33,894
– – 0.04% 223
2014
Q4 		$704K Hold
33,894
– – 0.02% 206
2014
Q3 		$751K Hold
33,894
– – 0.02% 204
2014
Q2 		$764K Hold
33,894
– – 0.02% 208
2014
Q1 		$1.3M Hold
33,894
– – 0.04% 201
2013
Q4 		$899K Hold
33,894
– – 0.02% 206
2013
Q3 		$686K Sell
33,894
-3,500
-9% -$61.9K 0.02% 210
2013
Q2 		$483K Buy
+37,394
New +$348K 0.01% 223

Other funds holding PRTA

Fidelity Investments
Fidelity Investments Boston, Massachusetts $1.9T AUM 41.92% 1-Year Est. Return
BlackRock
BlackRock New York $5.72T AUM 30.48% 1-Year Est. Return
Vanguard Group
Vanguard Group Malvern, Pennsylvania $6.9T AUM 27.45% 1-Year Est. Return
AC
Armistice Capital New York $5.62B AUM 36.06% 1-Year Est. Return
RCMNY
Rubric Capital Management (New York) New York $9.44B AUM 68.42% 1-Year Est. Return
ACM
ADAR1 Capital Management Austin, Texas $1.7B AUM 340.85% 1-Year Est. Return
PAI
Palo Alto Investors Palo Alto, California $654M AUM 77.8% 1-Year Est. Return
D.E. Shaw & Co
D.E. Shaw & Co New York $166B AUM 43.98% 1-Year Est. Return
Acadian Asset Management
Acadian Asset Management Boston, Massachusetts $70.5B AUM 36% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.61T AUM 30.72% 1-Year Est. Return

Granahan Investment Management's PRTA Position: Q3 2025 in Review

Granahan Investment Management sold out of Prothena Corp (PRTA) in Q3 2025, closing a stake of 461,082 shares — an estimated $2.8M sold.

Granahan Investment Management first reported a position in PRTA in Q2 2013 and held it in 23 quarters. The position peaked at $20.1M in Q2 2023. 187 funds tracked by Wall St. Rank hold PRTA as of Q3 2025.

  • Granahan Investment Management reported no remaining Prothena Corp position as of Q3 2025 after selling out during the quarter.
  • Granahan Investment Management sold 461,082 Prothena Corp shares in Q3 2025, an estimated $2.8M.
  • Granahan Investment Management first reported a position in Prothena Corp in Q2 2013 and held it in 23 quarters.
  • Granahan Investment Management's Prothena Corp position peaked at $20.1M in Q2 2023.
  • 187 funds tracked by Wall St. Rank held Prothena Corp as of Q3 2025.

Based on Granahan Investment Management's 13F filing for Q3 2025, filed 14 Nov 2025.