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Prothena Corp (PRTA)
NASDAQ
$8.38-$0.16 (-1.87%)
Price as of Oct 02, 2026 5:10 PM EDT- $438.4MMarket Cap
- -14.51%1-Year Change
- BiotechnologyIndustry
Prothena Corp (PRTA)
$8.38-$0.16 (-1.87%)
Top Holders
Institutional
Mutual Funds
Holder | Ownership %
| Shares Held | Change (Shares, %) | Report Date |
|---|---|---|---|---|
FMR LLC | 13.75% | 7.2M | -352,000 (-4.89%) | Jun 30, 2026 |
RUBRIC CAPITAL MANAGEMENT LP | 9.55% | 5.0M | 0 (0.00%) | Jun 30, 2026 |
BLACKROCK, INC. | 9.30% | 4.9M | +223,795 (+4.60%) | Jun 30, 2026 |
BLACKROCK FUNDING, INC. /DE | 7.87% | 4.1M | +93,989 (+2.28%) | Dec 31, 2024 |
BLACKROCK INC. | 7.37% | 3.9M | +138,266 (+3.58%) | Jun 30, 2024 |
STATE STREET CORP | 4.57% | 2.4M | +454,926 (+19.01%) | Jun 30, 2026 |
VANGUARD GROUP INC | 4.09% | 2.1M | +91,060 (+4.25%) | Dec 31, 2025 |
Holder | Ownership %
| Shares Held | Change (Shares, %) | Report Date |
|---|---|---|---|---|
VANGUARD SPECIALIZED FUNDS | 7.99% | 4.2M | 0 (0.00%) | Jul 31, 2026 |
FIDELITY MT VERNON STREET TRUST | 7.49% | 3.9M | 0 (0.00%) | May 31, 2026 |
SPDR SERIES TRUST | 3.54% | 1.9M | 0 (0.00%) | Jul 31, 2026 |
T. Rowe Price New Horizons Fund, Inc. | 3.37% | 1.8M | 0 (0.00%) | Jun 30, 2026 |
FIDELITY SELECT PORTFOLIOS | 1.68% | 877,217 | 0 (0.00%) | Jul 31, 2026 |
T. Rowe Price Health Sciences Fund, Inc. | 1.62% | 847,697 | 0 (0.00%) | Jun 30, 2026 |
VANGUARD EXPLORER FUND | 1.45% | 757,200 | +139,978 (+18.49%) | Jul 31, 2026 |
Current Ownership Distribution
- Institutions946.4M (81.45%)
- Mutual Funds204.1M (17.57%)
- Insiders11.3M (0.98%)
- Other0 (0.00%)
Insider Transactions
- 0.98% (11.3M)Current InsiderOwnership (%, shares)
- 1Number of InsiderBuying (last 12 months)
- $8.1MAmount 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 | 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 |
Smith Brandon S. Chief Operating Officer | Award | Mar 03, 2026 | $0.00 | 190,000 | $0.00 | 190,000 |
Swanson Chad J. Chief Development Officer | Award | Mar 03, 2026 | $0.00 | 190,000 | $0.00 | 190,000 |
Nguyen Tran Chief Strategy Officer and CFO | Award | Jul 28, 2025 | $0.00 | 95,000 | $0.00 | 97,205 |