PRTA — PROTHENA CORP PUBLIC LTD CO
Price · 2024-08-26 → 2026-08-21
499 daily closes shownAnonymous view is capped at two years of history. A free account extends it to five, and Pro opens the whole archive back to 2016-01-04.
Performance
Technicals
Others in Healthcare
Measured signals that fired on PRTA
| date | signal | measured base rate |
|---|---|---|
| 2026-06-09 | Equal lows taken out structure | -0.64% over 21 days · t = -4.75 · n = 55,661 statistically distinguishable from its control group |
| 2026-04-28 | Breakout to a 52-week high price | -1.00% over 21 days · t = -8.58 · n = 24,386 statistically distinguishable from its control group |
| 2026-04-23 | Equal highs taken out structure | -0.70% over 21 days · t = -8.28 · n = 68,636 statistically distinguishable from its control group |
| 2026-03-11 | Short volume far above its own normal short | -0.76% over 21 days · t = -2.79 · n = 5,897 statistically distinguishable from its control group |
Excess return against a matched control group, on a point-in-time universe that includes delisted companies. Most families do not survive that. How the measurement works →
Insider transactions (Form 4)
| date | insider | what | shares | price | value |
|---|---|---|---|---|---|
| 2026-08-20 | SCULLY WILLIAM P 10% owner | Open-market purchase | 50.0K | 8.79 | 439.4K |
| 2026-08-18 | SCULLY WILLIAM P 10% owner | Gift | 627.6K | 0.00 | 0 |
| 2026-08-17 | SCULLY WILLIAM P 10% owner | Gift | 336.0K | 0.00 | 0 |
| 2026-08-10 | SCULLY WILLIAM P 10% owner | Gift | 251.6K | 0.00 | 0 |
| 2026-08-07 | SCULLY WILLIAM P 10% owner | Open-market purchase | 34.0K | 8.62 | 293.1K |
| 2026-08-07 | SCULLY WILLIAM P 10% owner | Open-market purchase | 3.5K | 8.62 | 30.2K |
| 2026-07-29 | Isaacs Michael John General Counsel & Company Sec. | Open-market sale 10b5-1 plan | 8.4K | 8.47 | 71.1K |
| 2026-07-29 | Kingston Anne Evans Chief Strategy Officer | Open-market sale 10b5-1 plan | 7.7K | 8.47 | 64.9K |
| 2026-07-28 | Kinney Gene G. President and CEO | Disposition to issuer | 84.0K | 8.56 | 719.0K |
| 2026-07-28 | Smith Brandon S. Chief Operating Officer | Disposition to issuer | 78.0K | 8.56 | 667.7K |
Open-market purchases (code P) are the informative ones. Grants, option exercises and tax withholding are compensation mechanics, not decisions. How to read a Form 4 →
Largest institutional holders
| manager | value | shares |
|---|---|---|
| FMR LLC | 73.4M | 7.6M |
| Rubric Capital Management LP | 48.6M | 5.0M |
| BlackRock, Inc. | 45.1M | 4.6M |
| STATE STREET CORP | 18.8M | 1.9M |
| D. E. Shaw & Co., Inc. | 17.1M | 1.8M |
| ADAR1 Capital Management, LLC | 15.4M | 1.6M |
| VANGUARD PORTFOLIO MANAGEMENT LLC | 14.1M | 1.4M |
| MORGAN STANLEY | 12.0M | 1.2M |
| Palo Alto Investors LP | 11.7M | 1.2M |
| TWO SIGMA INVESTMENTS, LP | 11.7M | 1.2M |
13F positions as of 2026-03-31, filed up to 45 days after quarter end. Long-only US equity — shorts and derivatives never appear. What 13F does and does not show →
Latest SEC filings
| form | filed | period | |
|---|---|---|---|
| SCHEDULE 13G/A | 2026-08-14 | — | on EDGAR ↗ |
| 4 | 2026-08-11 | 2026-08-10 | on EDGAR ↗ |
| 3 | 2026-08-11 | 2026-08-06 | on EDGAR ↗ |
| 4 | 2026-08-10 | 2026-08-07 | on EDGAR ↗ |
| 10-Q | 2026-08-06 | 2026-06-30 | on EDGAR ↗ |
| 8-K | 2026-08-06 | 2026-08-06 | on EDGAR ↗ |
| SCHEDULE 13G/A | 2026-08-06 | — | on EDGAR ↗ |
| 4 | 2026-07-30 | 2026-07-28 | on EDGAR ↗ |
Short selling
This is off-exchange short volume, not short interest: it is flow, not position, and 40–50% is normal because market makers short to fill your buy. Why that number misleads →
Recent headlines
- PROTHENA CORP PUBLIC LTD CO (PRTA) filed form SCHEDULE 13G/A · 2026-08-14 · SEC EDGAR
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