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Prothena Corp (PRTA)
NASDAQ
$8.25+$0.21 (+2.68%)
Price as of Oct 22, 2026 7:30 PM EDT- $412.2MMarket Cap
- -18.72%1-Year Change
- BiotechnologyIndustry
Prothena Corp (PRTA)
$8.25+$0.21 (+2.68%)
Top Holders
Institutional
Mutual Funds
Holder | Ownership %
| Shares Held | Change (Shares, %) | Report Date |
|---|---|---|---|---|
FMR LLC | 14.02% | 7.2M | -352,000 (-4.89%) | Jun 30, 2026 |
RUBRIC CAPITAL MANAGEMENT LP | 9.74% | 5.0M | 0 (0.00%) | Jun 30, 2026 |
BLACKROCK, INC. | 9.48% | 4.9M | +223,795 (+4.60%) | Jun 30, 2026 |
BLACKROCK FUNDING, INC. /DE | 8.03% | 4.1M | +93,989 (+2.28%) | Dec 31, 2024 |
BLACKROCK INC. | 7.51% | 3.9M | +138,266 (+3.58%) | Jun 30, 2024 |
STATE STREET CORP | 4.66% | 2.4M | +454,926 (+19.01%) | Jun 30, 2026 |
VANGUARD GROUP INC | 4.17% | 2.1M | +91,060 (+4.25%) | Dec 31, 2025 |
Holder | Ownership %
| Shares Held | Change (Shares, %) | Report Date |
|---|---|---|---|---|
VANGUARD EXPLORER FUND | 1.47% | 757,200 | +139,978 (+18.49%) | Jul 31, 2026 |
VANGUARD INDEX FUNDS | 0.94% | 480,189 | -3,469 (-0.72%) | Jun 30, 2026 |
VANGUARD HORIZON FUNDS | 0.65% | 333,148 | 0 (0.00%) | Jun 30, 2026 |
VANGUARD SCOTTSDALE FUNDS | 0.51% | 263,999 | +9,822 (+3.72%) | May 31, 2026 |
Dimensional ETF Trust | 0.45% | 230,155 | +7,324 (+3.18%) | Jul 31, 2026 |
Bridge Builder Trust | 0.43% | 218,942 | +450 (+0.21%) | Jun 30, 2026 |
VANGUARD WORLD FUND | 0.27% | 136,559 | -1,151 (-0.84%) | May 31, 2026 |
Current Ownership Distribution
- Institutions946.8M (81.45%)
- Mutual Funds204.2M (17.57%)
- Insiders11.4M (0.98%)
- Other0 (0.00%)
Insider Transactions
- 0.98% (11.4M)Current InsiderOwnership (%, shares)
- 1Number of InsiderBuying (last 12 months)
- $16.4MAmount of InsiderBuying (last 12 months)
- 1Number of InsiderSelling (last 12 months)
- $231,815.54Amount of InsiderSelling (last 12 months)
Insider Name & Title | Type | Date
| Transaction Value | Shares | Share Price | Shares After Transactions |
|---|---|---|---|---|---|---|
SCULLY WILLIAM P | Buy | Oct 08, 2026 | $770,904.00 | 90,000 | $8.57 | 529,000 |
SCULLY WILLIAM P | Buy | Oct 07, 2026 | $1.1M | 125,000 | $8.40 | 439,000 |
SCULLY WILLIAM P | Buy | Oct 02, 2026 | $857,240.00 | 100,000 | $8.57 | 314,000 |
SCULLY WILLIAM P | Buy | Sep 29, 2026 | $1.4M | 162,000 | $8.68 | 214,000 |
SCULLY WILLIAM P | Buy | Sep 28, 2026 | $889,872.30 | 103,500 | $8.60 | 187,000 |
SCULLY WILLIAM P | Buy | Sep 18, 2026 | $843,460.00 | 100,000 | $8.43 | 927,000 |
SCULLY WILLIAM P | Gift | Aug 18, 2026 | $0.00 | 627,553 | $0.00 | 750,000 |
SCULLY WILLIAM P | Gift | Aug 17, 2026 | $0.00 | 336,000 | $0.00 | 1.4M |
Isaacs Michael John General Counsel & Company Sec. | Sell | Jul 29, 2026 | $71,055.42 | 8,386 | $8.47 | 35,745 |
Smith Brandon S. Chief Operating Officer | Exempt | Jul 28, 2026 | $0.00 | 78,000 | $0.00 | 0 |
Swanson Chad J. Chief Development Officer | Exempt | Jul 28, 2026 | $0.00 | 51,000 | $0.00 | 0 |
Zago Wagner M. Chief Scientific Officer | Exempt | Jul 28, 2026 | $0.00 | 51,000 | $0.00 | 0 |
Walker Karin L Chief Accounting Officer | Exempt | Jul 28, 2026 | $0.00 | 15,000 | $0.00 | 0 |
Smith Brandon S. Chief Operating Officer | Exempt | Jul 28, 2026 | $0.00 | 78,000 | $0.00 | 130,000 |
Swanson Chad J. Chief Development Officer | Exempt | Jul 28, 2026 | $0.00 | 51,000 | $0.00 | 85,000 |
Zago Wagner M. Chief Scientific Officer | Exempt | Jul 28, 2026 | $0.00 | 51,000 | $0.00 | 85,000 |
Nguyen Tran Chief Strategy Officer and CFO | Exempt | Jul 28, 2026 | $0.00 | 57,000 | $0.00 | 0 |
Smith Brandon S. Chief Operating Officer | Return | Jul 28, 2026 | $667,680.00 | 78,000 | $8.56 | 52,000 |
Swanson Chad J. Chief Development Officer | Return | Jul 28, 2026 | $349,248.00 | 40,800 | $8.56 | 44,200 |
Zago Wagner M. Chief Scientific Officer | Return | Jul 28, 2026 | $436,560.00 | 51,000 | $8.56 | 34,000 |
Walker Karin L Chief Accounting Officer | Exempt | Jul 28, 2026 | $0.00 | 15,000 | $0.00 | 25,000 |
Swanson Chad J. Chief Development Officer | In Kind | Jul 28, 2026 | $29,677.52 | 3,467 | $8.56 | 40,733 |
Isaacs Michael John General Counsel & Company Sec. | In Kind | Jul 28, 2026 | $40,180.64 | 4,694 | $8.56 | 44,131 |
Walker Karin L Chief Accounting Officer | Return | Jul 28, 2026 | $128,400.00 | 15,000 | $8.56 | 10,000 |
Nguyen Tran Chief Strategy Officer and CFO | Exempt | Jul 28, 2026 | $0.00 | 57,000 | $0.00 | 97,205 |
Nguyen Tran Chief Strategy Officer and CFO | Return | Jul 28, 2026 | $487,920.00 | 57,000 | $8.56 | 40,205 |
SCULLY WILLIAM P | Gift | Jun 15, 2026 | $0.00 | 325,000 | $0.00 | 736,000 |
Walker Karin L Chief Accounting Officer | Award | Mar 03, 2026 | $0.00 | 150,000 | $0.00 | 150,000 |
Zago Wagner M. Chief Scientific Officer | Award | Mar 03, 2026 | $0.00 | 190,000 | $0.00 | 190,000 |
Malecek Michael J Chief Legal Officer | Award | Mar 03, 2026 | $0.00 | 190,000 | $0.00 | 190,000 |