PRTA

Prothena Corp PLC
Health CareUSCUSIP G72800108◍ Confluence graph
Tracked 13F Holders
176
-98 QoQ
13F Value (tracked)
$442.1M
Insider Net · 180d
$3.7M
1↑ 2↓
Recent Filings
15
Smart-money sentimentBullish
BearishBullish
13F funds (latest Q)32 adding · 14 trimming
Insider net (180d)+$3.7M

Who owns PRTA?

176 tracked 13F filers

176 tracked 13F filers disclose a position in PRTA as of the latest SEC 13F filings, a combined $442.1M in reported value. Holders and values reflect the 13F filers Arkolith currently tracks, not the entire institutional universe. Counts and totals are a floor, not the full institutional ownership.

All quarters use one ordinary-share-equivalent series. Historical ADS are converted at 2 ADS = 1 ordinary share. Expand a row for the exact calculation; the residual is not classified as a trade.
#FundPosition valueSharesLast moveAs ofHistory
1FMR LLC
$73.4M
7.6M
Held
Q1 2026
2Rubric Capital Management LP
$48.6M
5.0M
+36%
Added · +1.3M sh
Q1 2026
3BlackRock, Inc.
$45.1M
4.6M
+13%
Added · +537K sh
Q1 2026
4STATE STREET CORP
$23.4M
2.4M
+23%
Added · +455K sh
Q2 2026
5D. E. Shaw & Co., Inc.
$17.1M
1.8M
+4.9%
Added · +82K sh
Q1 2026
6ADAR1 Capital Management, LLC
$15.4M
1.6M
+8.5%
Added · +124K sh
Q1 2026
7VANGUARD PORTFOLIO MANAGEMENT LLC
$14.1M
1.4M
First observed position
No prior filed position
Q1 2026
8MORGAN STANLEY
$12.0M
1.2M
−1.3%
Reduced · −16K sh
Q1 2026
9TWO SIGMA INVESTMENTS, LP
$11.7M
1.2M
+80%
Added · +536K sh
Q1 2026
10Palo Alto Investors LP
$11.2M
1.1M
−5.4%
Reduced · −65K sh
Q2 2026
11GEODE CAPITAL MANAGEMENT, LLC
$11.0M
1.1M
+2.5%
Added · +28K sh
Q2 2026
12FEDERATED HERMES, INC.
$10.3M
1.1M
+8.8%
Added · +85K sh
Q1 2026
13JACOBS LEVY EQUITY MANAGEMENT, INC
$9.4M
972K
−0.6%
Reduced · −6K sh
Q1 2026
14GOLDMAN SACHS GROUP INC
$8.0M
819K
−12%
Reduced · −116K sh
Q1 2026
15DIMENSIONAL FUND ADVISORS LP
$7.6M
783K
+0.9%
Added · +7K sh
Q1 2026
16Nuveen, LLC
$7.4M
759K
~0%
Added · +261 sh
Q1 2026
17Man Group plc
$6.6M
678K
+78%
Added · +297K sh
Q2 2026
18Qube Research & Technologies Ltd
$6.0M
615K
+51%
Added · +207K sh
Q1 2026
19RENAISSANCE TECHNOLOGIES LLC
$5.9M
608K
+39%
Added · +172K sh
Q1 2026
20Mariner, LLC
$5.5M
563K
−2.6%
Reduced · −15K sh
Q1 2026
21MONIMUS CAPITAL MANAGEMENT, LP
$4.7M
486K
+91%
Added · +231K sh
Q1 2026
22VANGUARD CAPITAL MANAGEMENT LLC
$4.7M
484K
First observed position
No prior filed position
Q1 2026
23Rangeley Capital, LLC
$4.4M
449K
−14%
Reduced · −75K sh
Q1 2026
24Birchview Capital, LP
$4.4M
449K
Held
Q2 2026
25ARMISTICE CAPITAL, LLC
$4.3M
439K
−71%
Reduced · −1.1M sh
Q1 2026

Holders and values reflect the 13F filers Arkolith currently tracks, not the entire institutional universe. Counts and totals are a floor, not the full institutional ownership.

Is PRTA being bought or sold by institutions?

Last quarter, 2 funds opened a new position in PRTA and 30 added to an existing one, while 14 reduced and 0 exited entirely — based on 13F filings from active, signal-eligible managers (passive index funds and other mechanical holders are excluded from this count).

Opened (NEW)
2
funds
Added
30
funds
Reduced
14
funds
Exited
0
funds

Funds that own PRTA also own

CompanyCo-held byCombined value
MICROSOFT CORPMSFT95 funds$145.4B
NVIDIA CORPNVDA94 funds$215.1B
AMAZON.COM INCAMZN93 funds$102.9B
META PLATFORMS INC-CLASS AMETA92 funds$59.6B
ALPHABET INC-CL AGOOGL91 funds$82.7B
ELI LILLY & COLLY91 funds$39.3B
APPLE INCAAPL89 funds$163.7B
MICRON TECHNOLOGY INCMU89 funds$20.9B
BRISTOL-MYERS SQUIBB COBMY89 funds$7.1B
COSTCO WHOLESALE CORPCOST88 funds$20.5B
ORACLE CORPORCL88 funds$9.9B
VISA INC-CLASS A SHARESV87 funds$34.3B

Ranked by how many of PRTA's institutional holders also hold each name, a cross-fund conviction signal.

Insider activity (Form 4)

Full insider page →
Buys · 180d
$3.9M
1 insiders
Sells · 180d
$136K
2 insiders
Net
$3.7M
10 P/S txns
Signal
Net Buying
open-market
DateInsiderRoleActionSharesValue
Aug 20, 2026SCULLY WILLIAM P10% OwnerBuy (P)50K$439K
Aug 7, 2026SCULLY WILLIAM P10% OwnerBuy (P)4K$30K
Aug 7, 2026SCULLY WILLIAM P10% OwnerBuy (P)34K$293K
Jul 29, 2026Isaacs Michael JohnGeneral Counsel & Company Sec.Sell (S)8K$71K
Jul 29, 2026Kingston Anne EvansChief Strategy OfficerSell (S)8K$65K
Jun 16, 2026SCULLY WILLIAM P10% OwnerBuy (P)20K$158K
Jun 11, 2026SCULLY WILLIAM P10% OwnerBuy (P)125K$1.0M
Jun 4, 2026SCULLY WILLIAM P10% OwnerBuy (P)50K$465K
Jun 2, 2026SCULLY WILLIAM P10% OwnerBuy (P)50K$471K
May 22, 2026SCULLY WILLIAM P10% OwnerBuy (P)100K$981K
May 6, 2025EcoR1 Capital, LLC10% OwnerSell (S)2.0M$15.2M
May 5, 2025EcoR1 Capital, LLC10% OwnerSell (S)978K$7.9M

Institutional ownership over time

69 funds-55 since Q3 2024
084167Q3 2024Q1 2025Q3 2025Q1 2026Q2 2026
funds holding aggregate valuelatest $63.6M

Recent filings

15 shown

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Connected entities for PRTA

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Ask your agent what changed in PRTA

This stock page is the public Follow view. For one current, evidence-backed answer, use capital_change_brief through REST or MCP. It compares tracked 13F changes with qualifying Form 4 activity and cites the SEC evidence.

Copy-paste
curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://arkolith.com/api/v1/stocks/PRTA/capital-change-brief"
Ask your agent
Use Arkolith's capital_change_brief for PRTA.
Tell me what changed, whether insider activity
corroborates it, and cite the SEC evidence.

13F holdings + Form 4 insider transactions + end-of-day price history + the live filing stream, joined for PRTA. Filings are public domain, sourced to SEC EDGAR; price series derived from end-of-day closes.