Comparable stake leader
FMR LLC
SEC ownership of PROTHENA CORP PUBLIC LTD CO
Top holders, 13D/G large-stake signals, insider positions, and transaction flow tied to CIK 0001559053.
Disclosed value leader
FMR LLC
Comparable rows
50/50
Latest evidence
28 Jul 2026
- Public ticker
- PRTA on Nasdaq
- Parsed ownership sources
-
13F, 13D/G, and 3/4/5
Source: Parsed SEC ownership filingsUse: Compare filing families carefully
- Largest SEC-reported holder
-
FMR LLC
Ranking: Comparable ownership first, then disclosed value
- Comparable ownership rows
-
50 of 50
Meaning: Rows with safely comparable ownership %
- Latest 13D/G holder
-
FMR LLC
Source: Latest parsed Schedule 13D/G stake
- Latest parsed ownership date
-
28 Jul 2026
Freshness: Most recent filing date in this holder set
- Issuer CIK
- 0001559053
- Issuer location
- Dublin 2, Ireland
Ownership snapshot
CIK-linked ownership evidence from parsed SEC filings.
3 signals
Issuer
Names, identifiers, and filing context for this profile.
2 identity fields
Ownership snapshot
Top shareholders of PROTHENA CORP PUBLIC LTD CO (13F + 13D/G + 3/4/5)
Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.
Comparable stake leader
FMR LLC
Disclosed value leader
FMR LLC
Comparable rows
50/50
Latest evidence
28 Jul 2026
13F
13D/G
3/4/5
Lead comparable stake: 14%
13D/G row: FMR LLC
Showing 1-8 of 50 holder rows.
Quick read
FMR LLC leads the comparable SEC ownership view at 14%.
50 of 50 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.
Open SEC evidence
Opens FMR LLC's linked filing trail.
Comparable ownership
Top 5
FMR LLC
14%
William P. Scully
10%
Fennell Todd W.
9.8%
Rubric Capital Management LP
9.3%
BlackRock, Inc.
6.9%
Ownership % is shown only when SEC disclosures are safely comparable across share classes.
Detailed SEC evidence table Showing 1-8 of 50 holder rows
| Holder | Evidence | Ownership % | Position | 12M Net Δ | As of |
|---|---|---|---|---|---|
| FMR LLC |
13F
13D/G
Company
|
14%
from 13D/G
|
$70,480,344
7,199,218 shares
|
— | 30 Jun 2026 |
| William P. Scully |
13D/G
3/4/5
SCULLY WILLIAM P · 10%+ Owner
|
10%
|
$53,949,825
5,378,846 shares
|
+$972,910 | 07 May 2026 |
| Fennell Todd W. |
13D/G
|
9.8%
|
$46,300,217
5,010,846 shares
|
+$4,758,600 | 30 Jun 2026 |
| Rubric Capital Management LP |
13D/G
13F
Company
|
9.3%
|
$50,150,000
5,000,000 shares
|
+$13,266,370 | 31 Mar 2026 |
| BlackRock, Inc. |
13F
13D/G
Company
|
6.9%
from 13D/G
|
$47,657,280
4,867,955 shares
|
— | 30 Jun 2026 |
| ADAR1 Capital Management, LLC |
13F
13D/G
Company
|
2.7%
from 13D/G
|
$15,218,898
1,554,535 shares
|
— | 30 Jun 2026 |
| WELLINGTON MANAGEMENT GROUP LLP |
13D/G
|
0.2%
|
$821,299
108,208 shares
|
-$38,122,050 | 30 May 2025 |
| PRICE T ROWE ASSOCIATES INC /MD/ |
13F
13D/G
Company · T. Rowe Price Associates, Inc.
|
0.1%
from 13D/G
|
$1,070,000
109,252 shares
|
— | 30 Jun 2026 |
How to read this table
Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.
Forms 3/4/5 flow
Insider trading overview
Net insider flow leans to buying over the last 12 months. Net value: +$3,284,355.
Buys
$3,420,330
Insiders: 1
Sells
$135,975
Insiders: 2
Net
+$3,284,355
Shares: +366,452
Window
Last 12 months
4 rolling buckets
Buy value
Sell value
Shares: 382,500
Shares: 16,048
| Window (months) | Buy shares | Sell shares | Buy value | Sell value | Net value |
|---|---|---|---|---|---|
| 0-3 | 382,500 | 16,048 | $3,420,330 | $135,975 | +$3,284,355 |
| 3-6 | 0 | 0 | $0 | $0 | $0 |
| 6-9 | 0 | 0 | $0 | $0 | $0 |
| 9-12 | 0 | 0 | $0 | $0 | $0 |
Reporting owners
Insider holders from Forms 3/4/5
Showing 1-20 of 27 reporting-owner rows connected to PROTHENA CORP PUBLIC LTD CO. Open a relationship link for the CIK-to-CIK filing trail.
Rows
27
Largest Forms 3/4/5 holder
EcoR1 Capital, LLC
Net 12M change
+$3,284,356
Latest report
10 Aug 2026
| Name | Relationship | Holdings Value | Past Year Net Change | Change % | Valuation | Report Date |
|---|---|---|---|---|---|---|
| EcoR1 Capital, LLC | 10%+ Owner | $40,544,618 | Filing P/S | 02 May 2025 | ||
| William P. Scully | 10%+ Owner | $12,218,308 | +$3,420,330 | +39% | Mixed | 10 Aug 2026 |
| Gene G. Kinney | President and CEO, Director | $673,483 | Median | 28 Jul 2026 | ||
| Brandon S. Smith | Chief Operating Officer | $509,080 | Median | 28 Jul 2026 | ||
| Michael J. Malecek | Chief Legal Officer | $485,600 | Mixed | 03 Mar 2026 | ||
| Anne E. Kingston | Chief Strategy Officer | $472,635 | -$64,919 | -12% | Filing P/S | 28 Jul 2026 |
| Chad J. Swanson | Chief Development Officer | $398,776 | Median | 28 Jul 2026 | ||
| Tran B. Nguyen | Chief Strategy Officer and CFO | $393,606 | Median | 28 Jul 2026 | ||
| Wagner M. Zago | Chief Scientific Officer | $332,860 | Median | 28 Jul 2026 | ||
| Michael J. Isaacs | General Counsel & Company Sec. | $302,870 | -$71,055 | -19% | Filing P/S | 28 Jul 2026 |
| Karin L. Walker | Chief Accounting Officer | $97,900 | Median | 28 Jul 2026 | ||
| Lars G. Ekman | Director | Mixed | 15 May 2026 | |||
| Paula K. Cobb | Director | Mixed | 14 May 2025 | |||
| Carol D. Karp | Chief Regulatory Officer | Mixed | 05 Mar 2025 | |||
| William H. Dunn Jr. | Director | Mixed | 15 May 2026 | |||
| David A. Ford | Chief People Officer | Mixed | 05 Mar 2025 | |||
| Fennell Todd W. | 10%+ Owner | Mixed | 06 Aug 2026 | |||
| Daniel G. Welch | Director | Mixed | 15 May 2026 | |||
| Helen Susan Kim | Director | Mixed | 14 May 2025 | |||
| Shane Cooke | Director | Mixed | 15 May 2026 |
Recent insider transactions for PROTHENA CORP PUBLIC LTD CO
Showing up to 300 recent insider transactions from the last 12 months.
| Insider | Symbol | Class | Transaction | % | SEC-reported value | SEC-reported price | Shares | Shares owned | Date | Ownership |
|---|---|---|---|---|---|---|---|---|---|---|
| William P. Scully | PRTA | Ordinary Shares, par value $0.01 per share | Gift | 31.8% | 251,553 | 1,041,553 | 10 Aug 2026 | Direct | ||
| William P. Scully | PRTA | Ordinary Shares, par value $0.01 per share | Purchase | 4.38% | $30,167 | $8.62 | 3,500 | 83,500 | 07 Aug 2026 | By Manatee Equity Fund LLC |
| William P. Scully | PRTA | Ordinary Shares, par value $0.01 per share | Purchase | 4.5% | $293,053 | $8.62 | 34,000 | 790,000 | 07 Aug 2026 | Direct |
| Anne E. Kingston | PRTA | Ordinary Shares, par value $0.01 per share | Sale | -12.1% | $64,919 | $8.47 | -7,662 | 55,782 | 29 Jul 2026 | Direct |
| Michael J. Isaacs | PRTA | Ordinary Shares, par value $0.01 per share | Sale | -19% | $71,055 | $8.47 | -8,386 | 35,745 | 29 Jul 2026 | Direct |
| Wagner M. Zago | PRTA | Ordinary Shares, par value $0.01 per share | Disposed to Issuer | -60% | -51,000 | 34,000 | 28 Jul 2026 | Direct | ||
| Wagner M. Zago | PRTA | Ordinary Shares, par value $0.01 per share | Options Exercise | 150% | 51,000 | 85,000 | 28 Jul 2026 | Direct | ||
| Wagner M. Zago | PRTA | Restricted Stock Units | Options Exercise | -100% | -51,000 | 0 | 28 Jul 2026 | Direct | ||
| Karin L. Walker | PRTA | Ordinary Shares, par value $0.01 per share | Disposed to Issuer | -60% | -15,000 | 10,000 | 28 Jul 2026 | Direct | ||
| Karin L. Walker | PRTA | Ordinary Shares, par value $0.01 per share | Options Exercise | 150% | 15,000 | 25,000 | 28 Jul 2026 | Direct | ||
| Karin L. Walker | PRTA | Restricted Stock Units | Options Exercise | -100% | -15,000 | 0 | 28 Jul 2026 | Direct | ||
| Chad J. Swanson | PRTA | Ordinary Shares, par value $0.01 per share | Tax liability | -7.84% | -3,467 | 40,733 | 28 Jul 2026 | Direct | ||
| Chad J. Swanson | PRTA | Ordinary Shares, par value $0.01 per share | Disposed to Issuer | -48% | -40,800 | 44,200 | 28 Jul 2026 | Direct | ||
| Chad J. Swanson | PRTA | Ordinary Shares, par value $0.01 per share | Options Exercise | 150% | 51,000 | 85,000 | 28 Jul 2026 | Direct | ||
| Chad J. Swanson | PRTA | Restricted Stock Units | Options Exercise | -100% | -51,000 | 0 | 28 Jul 2026 | Direct | ||
| Brandon S. Smith | PRTA | Ordinary Shares, par value $0.01 per share | Disposed to Issuer | -60% | -78,000 | 52,000 | 28 Jul 2026 | Direct | ||
| Brandon S. Smith | PRTA | Ordinary Shares, par value $0.01 per share | Options Exercise | 150% | 78,000 | 130,000 | 28 Jul 2026 | Direct | ||
| Brandon S. Smith | PRTA | Restricted Stock Units | Options Exercise | -100% | -78,000 | 0 | 28 Jul 2026 | Direct | ||
| Tran B. Nguyen | PRTA | Ordinary Shares, par value $0.01 per share | Disposed to Issuer | -58.6% | -57,000 | 40,205 | 28 Jul 2026 | Direct | ||
| Tran B. Nguyen | PRTA | Ordinary Shares, par value $0.01 per share | Options Exercise | 141.8% | 57,000 | 97,205 | 28 Jul 2026 | Direct | ||
| Tran B. Nguyen | PRTA | Restricted Stock Units | Options Exercise | -100% | -57,000 | 0 | 28 Jul 2026 | Direct | ||
| Gene G. Kinney | PRTA | Ordinary Shares, par value $0.01 per share | Disposed to Issuer | -55% | -84,000 | 68,793 | 28 Jul 2026 | Direct | ||
| Gene G. Kinney | PRTA | Ordinary Shares, par value $0.01 per share | Options Exercise | 122.1% | 84,000 | 152,793 | 28 Jul 2026 | Direct | ||
| Gene G. Kinney | PRTA | Restricted Stock Units | Options Exercise | -100% | -84,000 | 0 | 28 Jul 2026 | Direct | ||
| Anne E. Kingston | PRTA | Ordinary Shares, par value $0.01 per share | Tax liability | -5.23% | -3,498 | 63,444 | 28 Jul 2026 | Direct | ||
| Michael J. Isaacs | PRTA | Ordinary Shares, par value $0.01 per share | Tax liability | -9.61% | -4,694 | 44,131 | 28 Jul 2026 | Direct | ||
| William P. Scully | PRTA | Ordinary Shares, par value $0.01 per share | Purchase | 2.72% | $157,990 | $7.90 | 20,000 | 756,000 | 16 Jun 2026 | Direct |
| William P. Scully | PRTA | Ordinary Shares, par value $0.01 per share | Gift | -30.6% | -325,000 | 736,000 | 15 Jun 2026 | Direct | ||
| William P. Scully | PRTA | Ordinary Shares, par value $0.01 per share | Purchase | 13.4% | $1,021,225 | $8.17 | 125,000 | 1,061,000 | 11 Jun 2026 | Direct |
| William P. Scully | PRTA | Ordinary Shares, par value $0.01 per share | Purchase | 5.64% | $465,295 | $9.31 | 50,000 | 936,000 | 04 Jun 2026 | Direct |
| William P. Scully | PRTA | Ordinary Shares, par value $0.01 per share | Purchase | 5.98% | $471,300 | $9.43 | 50,000 | 886,000 | 02 Jun 2026 | Direct |
| William P. Scully | PRTA | Ordinary Shares, par value $0.01 per share | Purchase | 13.6% | $981,300 | $9.81 | 100,000 | 836,000 | 22 May 2026 | Direct |
| Daniel G. Welch | PRTA | Stock Option (Right to Buy) | Award | 27,000 | 27,000 | 15 May 2026 | Direct | |||
| Dennis J. Selkoe | PRTA | Stock Option (Right to Buy) | Award | 27,000 | 27,000 | 15 May 2026 | Direct | |||
| Lars G. Ekman | PRTA | Stock Option (Right to Buy) | Award | 27,000 | 27,000 | 15 May 2026 | Direct | |||
| William H. Dunn Jr. | PRTA | Stock Option (Right to Buy) | Award | 27,000 | 27,000 | 15 May 2026 | Direct | |||
| Shane Cooke | PRTA | Stock Option (Right to Buy) | Award | 27,000 | 27,000 | 15 May 2026 | Direct | |||
| Richard T. Collier | PRTA | Stock Option (Right to Buy) | Award | 27,000 | 27,000 | 15 May 2026 | Direct | |||
| Anne E. Kingston | PRTA | Stock Option (Right to Buy) | Award | 100,000 | 100,000 | 10 Apr 2026 | Direct | |||
| Wagner M. Zago | PRTA | Stock Option (Right to Buy) | Award | 190,000 | 190,000 | 03 Mar 2026 | Direct | |||
| Karin L. Walker | PRTA | Stock Option (Right to Buy) | Award | 150,000 | 150,000 | 03 Mar 2026 | Direct | |||
| Chad J. Swanson | PRTA | Stock Option (Right to Buy) | Award | 190,000 | 190,000 | 03 Mar 2026 | Direct | |||
| Brandon S. Smith | PRTA | Stock Option (Right to Buy) | Award | 190,000 | 190,000 | 03 Mar 2026 | Direct | |||
| Tran B. Nguyen | PRTA | Stock Option (Right to Buy) | Award | 230,000 | 230,000 | 03 Mar 2026 | Direct | |||
| Michael J. Malecek | PRTA | Stock Option (Right to Buy) | Award | 190,000 | 190,000 | 03 Mar 2026 | Direct | |||
| Gene G. Kinney | PRTA | Stock Option (Right to Buy) | Award | 520,000 | 520,000 | 03 Mar 2026 | Direct |
* marks a reported price that did not pass the local price check.