PROTHENA CORP PUBLIC LTD CO
Total Trades
177
Buys
3
Sells
88
Largest Trade
$1M+
Insiders
14
Institutional Funds
137
Inst. Value
$1M+
Activist Filings
40
Insider Trades
| Insider | Title | Type | Value | Shares | Price | Date |
|---|---|---|---|---|---|---|
| EcoR1 Capital, LLC | 10% Owner | SELL | $1M+ | 6.3M | $8.10 | May 6, 2025 |
| SCULLY WILLIAM P | 10% Owner | BUY | $1M+ | 207K | $13.26 | May 2, 2025 |
| Walker Karin L | Chief Accounting O… | EXERCISE | $50K–$100K | 5K | $13.53 | Jan 25, 2024 |
| Walker Karin L | Chief Accounting O… | SELL | $100K–$500K | 5K | $34.00 | Jan 25, 2024 |
| Walker Karin L | Chief Accounting O… | SELL | $100K–$500K | 5K | $34.00 | Nov 30, 2023 |
| Walker Karin L | Chief Accounting O… | EXERCISE | $50K–$100K | 5K | $13.53 | Nov 30, 2023 |
| Walker Karin L | Chief Accounting O… | EXERCISE | $50K–$100K | 5K | $13.53 | Oct 26, 2023 |
| Walker Karin L | Chief Accounting O… | SELL | $100K–$500K | 5K | $41.04 | Oct 26, 2023 |
| Smith Brandon S. | COO | SELL | $100K–$500K | 4K | $46.75 | Oct 12, 2023 |
| Smith Brandon S. | COO | EXERCISE | $15K–$50K | 4K | $11.12 | Oct 12, 2023 |
| Karp Carol D. | Chief Regulatory O… | SELL | $100K–$500K | 5K | $46.62 | Oct 4, 2023 |
| Karp Carol D. | Chief Regulatory O… | EXERCISE | $50K–$100K | 5K | $12.15 | Oct 4, 2023 |
| Malecek Michael J | Chief Legal Officer | EXERCISE | $50K–$100K | 5K | $10.27 | Sep 28, 2023 |
| Malecek Michael J | Chief Legal Officer | SELL | $100K–$500K | 5K | $47.38 | Sep 28, 2023 |
| Walker Karin L | Chief Accounting O… | EXERCISE | $50K–$100K | 5K | $15.04 | Sep 19, 2023 |
| Walker Karin L | Chief Accounting O… | SELL | $100K–$500K | 5K | $52.36 | Sep 19, 2023 |
| Garren Hideki | Chief Medical Offi… | EXERCISE | $15K–$50K | 2K | $24.90 | Sep 13, 2023 |
| Garren Hideki | Chief Medical Offi… | SELL | $100K–$500K | 2K | $55.48 | Sep 13, 2023 |
| Smith Brandon S. | COO | EXERCISE | $15K–$50K | 4K | $11.12 | Sep 13, 2023 |
| Smith Brandon S. | COO | SELL | $100K–$500K | 4K | $55.49 | Sep 13, 2023 |
| Karp Carol D. | Chief Regulatory O… | EXERCISE | $50K–$100K | 5K | $12.15 | Sep 6, 2023 |
| Karp Carol D. | Chief Regulatory O… | SELL | $100K–$500K | 5K | $54.76 | Sep 6, 2023 |
| Malecek Michael J | Chief Legal Officer | SELL | $100K–$500K | 5K | $55.01 | Aug 30, 2023 |
| Malecek Michael J | Chief Legal Officer | EXERCISE | $50K–$100K | 5K | $10.27 | Aug 30, 2023 |
| Walker Karin L | Chief Accounting O… | EXERCISE | $50K–$100K | 5K | $15.04 | Aug 19, 2023 |
| Walker Karin L | Chief Accounting O… | SELL | $100K–$500K | 5K | $57.18 | Aug 19, 2023 |
| Garren Hideki | Chief Medical Offi… | SELL | $100K–$500K | 2K | $58.74 | Aug 17, 2023 |
| Garren Hideki | Chief Medical Offi… | EXERCISE | $15K–$50K | 2K | $24.90 | Aug 17, 2023 |
| Smith Brandon S. | COO | EXERCISE | $15K–$50K | 4K | $11.12 | Aug 17, 2023 |
| Smith Brandon S. | COO | SELL | $100K–$500K | 4K | $58.71 | Aug 17, 2023 |
| Zago Wagner M. | Chief Scientific O… | EXERCISE | $15K–$50K | 4K | $12.15 | Aug 3, 2023 |
| Zago Wagner M. | Chief Scientific O… | SELL | $100K–$500K | 4K | $67.05 | Aug 3, 2023 |
| Karp Carol D. | Chief Regulatory O… | EXERCISE | $50K–$100K | 5K | $12.15 | Aug 3, 2023 |
| Karp Carol D. | Chief Regulatory O… | SELL | $100K–$500K | 5K | $67.01 | Aug 3, 2023 |
| Malecek Michael J | Chief Legal Officer | SELL | $100K–$500K | 5K | $62.33 | Jul 26, 2023 |
| Malecek Michael J | Chief Legal Officer | EXERCISE | $50K–$100K | 5K | $10.27 | Jul 26, 2023 |
| Walker Karin L | Chief Accounting O… | SELL | $100K–$500K | 5K | $69.19 | Jul 20, 2023 |
| Walker Karin L | Chief Accounting O… | EXERCISE | $50K–$100K | 5K | $15.04 | Jul 20, 2023 |
| Garren Hideki | Chief Medical Offi… | SELL | $100K–$500K | 2K | $67.51 | Jul 13, 2023 |
| Garren Hideki | Chief Medical Offi… | EXERCISE | $15K–$50K | 2K | $24.90 | Jul 13, 2023 |
| Smith Brandon S. | COO | EXERCISE | $15K–$50K | 4K | $11.12 | Jul 13, 2023 |
| Smith Brandon S. | COO | SELL | $100K–$500K | 4K | $67.51 | Jul 13, 2023 |
| Karp Carol D. | Chief Regulatory O… | EXERCISE | $50K–$100K | 5K | $12.15 | Jul 6, 2023 |
| Karp Carol D. | Chief Regulatory O… | SELL | $100K–$500K | 5K | $68.13 | Jul 6, 2023 |
| Zago Wagner M. | Chief Scientific O… | EXERCISE | $15K–$50K | 4K | $12.15 | Jul 6, 2023 |
| Zago Wagner M. | Chief Scientific O… | SELL | $100K–$500K | 4K | $68.16 | Jul 6, 2023 |
| Selkoe Dennis J. | Director | EXERCISE | $50K–$100K | 5K | $11.33 | Jul 3, 2023 |
| Selkoe Dennis J. | Director | SELL | $100K–$500K | 5K | $67.43 | Jul 3, 2023 |
| Malecek Michael J | Chief Legal Officer | EXERCISE | $50K–$100K | 5K | $10.27 | Jun 29, 2023 |
| Malecek Michael J | Chief Legal Officer | SELL | $100K–$500K | 5K | $69.82 | Jun 29, 2023 |
Institutional Ownership
13F filings as of Dec 31, 2025 · 137 funds holding
| Fund | Shares | Value | Type |
|---|---|---|---|
| Rubric Capital Management LP | 3.7M | $1M+ | SH |
| STATE STREET CORP | 2.3M | $1M+ | SH |
| ADAR1 Capital Management, LLC | 1.5M | $1M+ | SH |
| ADAR1 Capital Management, LLC | 1.5M | $1M+ | SH |
| ACADIAN ASSET MANAGEMENT LLC | 1.4M | $1M+ | SH |
| Palo Alto Investors LP | 1.3M | $1M+ | SH |
| JACOBS LEVY EQUITY MANAGEMENT, INC | 978K | $1M+ | SH |
| GEODE CAPITAL MANAGEMENT, LLC | 919K | $1M+ | SH |
| Point72 Asset Management, L.P. | 860K | $1M+ | SH |
| DIMENSIONAL FUND ADVISORS LP | 744K | $1M+ | SH |
| Mariner, LLC | 578K | $1M+ | SH |
| Birchview Capital, LP | 441K | $1M+ | SH |
| RENAISSANCE TECHNOLOGIES LLC | 436K | $1M+ | SH |
| BNP PARIBAS FINANCIAL MARKETS | 424K | $1M+ | SH |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC | 357K | $1M+ | SH |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP | 298K | $1M+ | SH |
| Man Group plc | 270K | $1M+ | SH |
| JANE STREET GROUP, LLC | 245K | $1M+ | SH |
| VANGUARD GROUP INC | 241K | $1M+ | SH |
| Squarepoint Ops LLC | 218K | $1M+ | SH |
Activist & 5%+ Owners
SC 13D/13G filings — investors holding 5%+ of outstanding shares
SC 13G · Feb 13, 2026
6.8%
3.7M shares
SC 13G/A · Nov 15, 2025
2.7%
1.5M shares
SC 13G/A · Nov 12, 2025
8.4%
4.5M shares
SC 13G/A · Nov 12, 2025
9.8%
5.3M shares
SC 13G/A · Oct 17, 2025
5.7%
3.1M shares
SC 13G · Aug 15, 2025
6.3%
3.4M shares
SC 13G/A · Aug 14, 2025
0.0%
0 shares
T. Rowe Price Associates, Inc.
SC 13G/A · Aug 14, 2025
0.1%
71K shares
SC 13G/A · Aug 13, 2025
9.9%
5.4M shares
SC 13G/A · Aug 13, 2025
8.1%
4.4M shares
Wellington Management Group LLP
SC 13G/A · Jun 5, 2025
0.2%
108K shares
SC 13G · Jun 4, 2025
5.5%
3.0M shares
SC 13D/A · May 30, 2025
0.0%
0 shares
SC 13G/A · May 15, 2025
8.5%
4.6M shares
SC 13G/A · May 14, 2025
10.4%
5.6M shares
SC 13D/A · May 6, 2025
9.9%
5.3M shares
SC 13G/A · Feb 21, 2025
10.3%
5.6M shares
SC 13G/A · Feb 14, 2025
8.6%
4.6M shares
Wellington Management Group LLP
SC 13G/A · Feb 10, 2025
9.5%
5.1M shares
SC 13D/A · Jan 4, 2025
21.5%
11.6M shares
T. ROWE PRICE ASSOCIATES, INC. 52-0556948
SC 13G/A · Nov 14, 2024
7.1%
3.8M shares
SC 13G/A · Nov 13, 2024
5.9%
3.2M shares
SC 13G/A · Nov 13, 2024
7.5%
403.6M shares
Wellington Management Group LLP
SC 13G · Nov 8, 2024
7.8%
4.2M shares
Wellington Management Group LLP
SC 13G/A · Nov 7, 2024
10.8%
5.8M shares
STATE STREET CORPORATION 04-2456637
SC 13G/A · Oct 18, 2024
3.1%
1.7M shares
SC 13G · Feb 14, 2024
5.8%
3.1M shares
SC 13G · Feb 14, 2024
6.5%
350.2M shares
T. ROWE PRICE ASSOCIATES, INC. 52-0556948
SC 13G/A · Feb 14, 2024
7.9%
4.2M shares
Avidity Partners Management LP
SC 13G/A · Feb 14, 2024
0.0%
0 shares
STATE STREET CORPORATION I.R.S. IDENTIFICATION NO. OF THE ABOVE PERSON 04-2456637
SC 13G · Jan 24, 2024
5.1%
0 shares
SC 13G/A · Mar 10, 2023
10.0%
5.3M shares
Avidity Partners Management LP
SC 13G/A · Feb 14, 2023
5.7%
3.0M shares
SC 13G/A · Feb 14, 2023
4.8%
2.5M shares
T. ROWE PRICE ASSOCIATES, INC. 52-0556948
SC 13G/A · Feb 14, 2023
6.3%
3.2M shares
T. ROWE PRICE ASSOCIATES, INC. 52-0556948
SC 13G/A · Aug 10, 2022
6.4%
3.0M shares
SC 13G · Jun 27, 2022
5.4%
2.5M shares
First Light Asset Management, LLC 46-3521994
SC 13G · Mar 1, 2022
3.9%
1.8M shares
T. ROWE PRICE ASSOCIATES, INC. 52-0556948
SC 13G/A · Feb 14, 2022
12.7%
5.9M shares
SC 13D/A · Jan 13, 2022
24.9%
11.6M shares