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Prothena Corp
PRTA

Overview Fund Activity

185 hedge funds and large institutions have $253M invested in Prothena Corp in 2025 Q2 according to their latest regulatory filings, with 52 funds opening new positions, 53 increasing their positions, 41 reducing their positions, and 22 closing their positions.

Holders
185
Holders Change
+26
Holders Change %
+16.35%
% of All Funds
2.48%
Holding in Top 10
3
Holding in Top 10 Change
–
Holding in Top 10 Change %
–
% of All Funds
0.04%
New
52
Increased
53
Reduced
41
Closed
22
Calls
$4.37M
Puts
$3.43M
Net Calls
+$940K
Net Calls Change
-$1.31M

Top Buyers

1
ACM
1
ADAR1 Capital Management
Texas
$20.5M
2
Citadel Advisors
2
Citadel Advisors
Florida
$6.97M
3
Acadian Asset Management
3
Acadian Asset Management
Massachusetts
$6.18M
4
Vanguard Group
4
Vanguard Group
Pennsylvania
$13.2M
5
RC
5
Rangeley Capital
Connecticut
$4.34M

Top Sellers

1
EC
1
EcoR1 Capital
California
$0
2
Wellington Management Group
2
Wellington Management Group
Massachusetts
$655K
3
T. Rowe Price Associates
3
T. Rowe Price Associates
Maryland
$432K
4
SL
4
Siren LLC
Connecticut
$0
5
BCM
5
Boxer Capital Management
California
$0
Name Market Value Shares Shares
Change 		Shares
Change %
Fidelity Investments
1
Fidelity Investments
Massachusetts
$48M 7,901,218 -40,184 -0.5%
BlackRock
2
BlackRock
New York
$23.9M 3,939,398 -102,903 -3%
ACM
3
ADAR1 Capital Management
Texas
$20.5M 3,375,009 +3,375,009 New
AC
4
Armistice Capital
New York
$13.6M 2,236,000 +40,000 +2%
Vanguard Group
5
Vanguard Group
Pennsylvania
$13.2M 2,176,227 +906,956 +71%
PAI
6
Palo Alto Investors
California
$7.74M 1,274,753 -384,981 -23%
Federated Hermes
7
Federated Hermes
Pennsylvania
$7.17M 1,181,087 +634,832 +116%
Citadel Advisors
8
Citadel Advisors
Florida
$6.97M 1,147,622 +1,058,223 +1,184%
Acadian Asset Management
9
Acadian Asset Management
Massachusetts
$6.18M 1,018,177 +1,018,177 New
State Street
10
State Street
Massachusetts
$6.1M 1,005,002 -516,362 -34%
Dimensional Fund Advisors
11
Dimensional Fund Advisors
Texas
$5.84M 962,339 +99,191 +11%
Morgan Stanley
12
Morgan Stanley
New York
$5.79M 953,256 +233,268 +32%
Geode Capital Management
13
Geode Capital Management
Massachusetts
$5.67M 933,446 -81,346 -8%
RC
14
Rangeley Capital
Connecticut
$4.34M 715,367 +715,367 New
Jacobs Levy Equity Management
15
Jacobs Levy Equity Management
New Jersey
$4.21M 693,154 +674,601 +3,636%
Balyasny Asset Management
16
Balyasny Asset Management
Illinois
$3.5M 575,792 +575,792 New
TI
17
Trexquant Investment
Connecticut
$3.36M 552,826 +552,826 New
Goldman Sachs
18
Goldman Sachs
New York
$3.21M 528,323 +17,861 +3%
CSS
19
Cubist Systematic Strategies
Connecticut
$3.05M 501,764 +501,764 New
RSCM
20
Rock Springs Capital Management
Maryland
$2.99M 492,601 – –
GIM
21
Granahan Investment Management
Massachusetts
$2.8M 461,082 +461,082 New
BC
22
Birchview Capital
Vermont
$2.74M 451,019 +118,045 +35%
Qube Research & Technologies (QRT)
23
Qube Research & Technologies (QRT)
United Kingdom
$2.52M 414,828 +414,828 New
D.E. Shaw & Co
24
D.E. Shaw & Co
New York
$2.38M 391,495 +373,692 +2,099%
Mariner
25
Mariner
Kansas
$2.35M 386,708 +32,058 +9%
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