Prothena Corp Public Ltd Co
PRTA- Exchange
- Nasdaq
- Industry
- Pharmaceutical Preparations
- SEC CIK
- 0001559053
In the last 90 days, Prothena Corp Public Ltd Co insiders filed 10 open-market purchases and 0 sales; 189 institutions reported holding it in 13F filings for Q2 2026, worth $462.7M in total; no superinvestor holds it.
Holders of 5% or more of PRTA
Holders whose latest Schedule 13D or 13G filing reports 5% or more of Prothena Corp Public Ltd Co, largest stake first. The change is against the holder's previous filing.
| Holder | Latest form | Stake | Change | First filed | Latest filing | Filing |
|---|---|---|---|---|---|---|
| FMR LLC | 13G/A | 13.80%7.20M shares | – | Feb 8, 20216 filings | Aug 6, 2026 | SEC |
| Scully William P | 13G/A | 10.30%5.38M shares | +0.50 ppfrom 9.80% | Jun 27, 20229 filings | May 11, 2026 | SEC |
| Fennell Todd W. | 13G/A | 10.20%5.25M shares | +0.40 ppfrom 9.80% | Feb 14, 20248 filings | Aug 19, 2026 | SEC |
| Rubric Capital Management LP | 13G/A | 9.29%5.00M shares | +2.46 ppfrom 6.83% | Feb 13, 20262 filings | May 15, 2026 | SEC |
| BlackRock, Inc. | 13G/A | 6.90%3.59M shares | +1.20 ppfrom 5.70% | Oct 17, 20252 filings | Jul 29, 2026 | SEC |
Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.
13D and 13G filings
59 Schedule 13D and 13G filings on Prothena Corp Public Ltd Co, newest first, including old-format filings without a stake.
| Filed (ET) | Filer | Form | Stake | Change | Event date | Filing |
|---|---|---|---|---|---|---|
| Aug 19, 202610:18 AM ET | Fennell Todd W. | 13G/A | 10.20%5.25M shares | +0.40 ppfrom 9.80% | Aug 18, 2026 | SEC |
| Aug 14, 20269:10 AM ET | Fennell Todd W. | 13G/A | 9.80%5.01M shares | +1.40 ppfrom 8.40% | Jun 30, 2026 | SEC |
| Aug 6, 202610:38 AM ET | FMR LLCand 1 other | 13G/A | 13.80%7.20M shares | – | Jun 30, 2026 | SEC |
| Jul 29, 20263:19 PM ET | BlackRock, Inc. | 13G/A | 6.90%3.59M shares | +1.20 ppfrom 5.70% | Jun 30, 2026 | SEC |
| May 15, 20264:07 PM ET | Rubric Capital Management LPand 1 other | 13G/A | 9.29%5.00M shares | +2.46 ppfrom 6.83% | Mar 31, 2026 | SEC |
| May 11, 20263:25 PM ET | Scully William P | 13G/A | 10.30%5.38M shares | +0.50 ppfrom 9.80% | May 7, 2026 | SEC |
| Feb 13, 20264:16 PM ET | Rubric Capital Management LPand 1 other | 13G | 6.83%3.68M shares | New | Dec 31, 2025 | SEC |
| Nov 14, 20257:47 PM ET | ADAR1 Capital Management, LLCand 2 others | 13G/A | 2.70%1.47M shares | −3.60 ppfrom 6.30%Below 5% | Sep 30, 2025 | SEC |
| Nov 12, 20253:51 PM ET | Fennell Todd W. | 13G/A | 8.40%4.50M shares | +0.30 ppfrom 8.10% | Sep 30, 2025 | SEC |
| Nov 12, 20253:47 PM ET | Scully William P | 13G/A | 9.80%5.28M shares | −0.10 ppfrom 9.90% | Sep 30, 2025 | SEC |
| Oct 17, 20254:07 PM ET | BlackRock, Inc. | 13G/A | 5.70%3.09M shares | – | Sep 30, 2025 | SEC |
| Aug 14, 20258:17 PM ET | ADAR1 Capital Management, LLCand 2 others | 13G | 6.30%3.38M shares | New | Jun 30, 2025 | SEC |
| Aug 14, 20251:16 PM ET | Logos Global Management LPand 4 others | 13G/A | 0.00%0 shares | −5.50 ppfrom 5.50%Below 5% | Jun 30, 2025 | SEC |
| Aug 14, 20251:07 PM ET | Price T Rowe Associates Inc | 13G/A | 0.10%71.0K shares | –Below 5% | Jun 30, 2025 | SEC |
| Aug 13, 20254:14 PM ET | Scully William P | 13G/A | 9.90%5.35M shares | −0.50 ppfrom 10.40% | Jun 30, 2025 | SEC |
| Aug 13, 20254:00 PM ET | Fennell Todd W. | 13G/A | 8.10%4.35M shares | −0.40 ppfrom 8.50% | Jun 30, 2025 | SEC |
| Jun 5, 20257:43 PM ET | Wellington Management Group LLPand 2 others | 13G/A | 0.20%108.2K shares | −9.30 ppfrom 9.50%Below 5% | May 30, 2025 | SEC |
| Jun 4, 20255:18 PM ET | Logos Global Management LPand 4 others | 13G | 5.50%2.95M shares | New | May 29, 2025 | SEC |
| May 29, 20259:08 PM ET | EcoR1 Capital, LLCand 2 others | 13D/A | 0.00%0 shares | −9.90 ppfrom 9.90%Below 5% | May 27, 2025 | SEC |
| May 15, 202510:00 AM ET | Fennell Todd W. | 13G/A | 8.50%4.59M shares | −0.10 ppfrom 8.60% | Mar 31, 2025 | SEC |
| May 14, 202510:34 AM ET | Scully William P | 13G/A | 10.40%5.61M shares | +0.10 ppfrom 10.30% | Mar 31, 2025 | SEC |
| May 6, 20257:08 PM ET | EcoR1 Capital, LLCand 2 others | 13D/A | 9.90%5.30M shares | −11.60 ppfrom 21.50% | May 2, 2025 | SEC |
| Feb 21, 20252:49 PM ET | Scully William P | 13G/A | 10.30%5.56M shares | – | Dec 31, 2024 | SEC |
| Feb 14, 20253:35 PM ET | Fennell Todd W. | 13G/A | 8.60%4.65M shares | – | Dec 31, 2024 | SEC |
| Feb 10, 202510:25 AM ET | Wellington Management Group LLPand 3 others | 13G/A | 9.50%5.13M shares | – | Dec 31, 2024 | SEC |
| Jan 3, 20257:45 PM ET | EcoR1 Capital, LLCand 2 others | 13D/A | 21.50%11.6M shares | – | Dec 31, 2024 | SEC |
| Nov 14, 2024 | Price T Rowe Associates Inc | 13G/AOld format | – | – | – | SEC |
| Nov 13, 2024 | Fennell Todd W. | 13G/AOld format | – | – | – | SEC |
| Nov 13, 2024 | Scully William P | 13G/AOld format | – | – | – | SEC |
| Nov 8, 2024 | Wellington Management Group LLP | 13GOld format | – | – | – | SEC |
| Nov 7, 2024 | Wellington Management Group LLP | 13G/AOld format | – | – | – | SEC |
| Oct 18, 2024 | State Street Corp | 13G/AOld format | – | – | – | SEC |
| Feb 14, 2024 | Fennell Todd W. | 13GOld format | – | New | – | SEC |
| Feb 14, 2024 | Scully William P | 13GOld format | – | – | – | SEC |
| Feb 14, 2024 | Price T Rowe Associates Inc | 13G/AOld format | – | – | – | SEC |
| Feb 13, 2024 | Avidity Partners Management LP | 13G/AOld format | – | – | – | SEC |
| Feb 9, 2024 | FMR LLC | 13G/AOld format | – | – | – | SEC |
| Feb 2, 20242:18 PM ET | BlackRock Inc. | 13G/AOld format | – | – | – | SEC |
| Jan 24, 2024 | State Street Corp | 13GOld format | – | New | – | SEC |
| Mar 10, 2023 | FMR LLC | 13G/AOld format | – | – | – | SEC |
| Feb 14, 2023 | Scully William P | 13G/AOld format | – | – | – | SEC |
| Feb 14, 2023 | Avidity Partners Management LP | 13G/AOld format | – | – | – | SEC |
| Feb 14, 2023 | Price T Rowe Associates Inc | 13G/AOld format | – | – | – | SEC |
| Feb 9, 2023 | FMR LLC | 13G/AOld format | – | – | – | SEC |
| Jan 31, 20235:52 PM ET | BlackRock Inc. | 13G/AOld format | – | – | – | SEC |
| Aug 10, 2022 | Price T Rowe Associates Inc | 13G/AOld format | – | – | – | SEC |
| Jun 27, 2022 | Scully William P | 13GOld format | – | New | – | SEC |
| Mar 1, 2022 | First Light Asset Management, LLC | 13GOld format | – | – | – | SEC |
| Feb 14, 2022 | Price T Rowe Associates Inc | 13G/AOld format | – | – | – | SEC |
| Feb 9, 2022 | FMR LLC | 13GOld format | – | – | – | SEC |
Form 144: proposed insider sales
43 notices from officers, directors and other affiliates planning to sell Prothena Corp Public Ltd Co shares, newest first.
| Filed (ET) | Seller | Shares to sell | Market value | Planned sale | Broker | Filing |
|---|---|---|---|---|---|---|
| Jul 29, 20264:12 PM ET | Anne KingstonOfficer | 7.66K | $64.9K | Jul 29, 202610b5-1 | Morgan Stanley Smith Barney LLC Executive Financial Services | SEC |
| Jul 29, 20264:12 PM ET | Michael John IsaacsOfficer | 8.39K | $71.1K | Jul 29, 202610b5-1 | Morgan Stanley Smith Barney LLC Executive Financial Services | SEC |
| Jun 9, 20268:00 AM ET | Malecek Michael JPrevious Officer | 80.0K | $740.0K | Jun 9, 2026 | ETRADE FINANCIAL CORPORATION | SEC |
| Jan 24, 20244:06 PM ET | Walker Karin LOfficer | 5.00K | $170.0K | Jan 24, 202410b5-1 | UBS Financial Services, Inc. | SEC |
| Dec 20, 20234:03 PM ET | Walker Karin LOfficer | 5.00K | $186.4K | Dec 20, 202310b5-1 | UBS Financial Services, Inc | SEC |
| Nov 30, 20234:05 PM ET | Walker Karin LOfficer | 5.00K | $170.0K | Nov 30, 202310b5-1 | UBS Financial Services, Inc. | SEC |
| Oct 25, 20234:01 PM ET | Walker Karin LOfficer | 5.00K | $206.3K | Oct 25, 202310b5-1 | UBS Financial Services, Inc. | SEC |
| Oct 11, 20234:02 PM ET | Smith Brandon S.Officer | 4.00K | $189.2K | Oct 11, 202310b5-1 | UBS Financial Services, Inc. | SEC |
| Oct 4, 20234:03 PM ET | Karp Carol D.Officer | 5.00K | $237.0K | Oct 4, 202310b5-1 | UBS Financial Services, Inc | SEC |
| Sep 27, 20234:01 PM ET | Malecek Michael JOfficer | 5.00K | $241.1K | Sep 27, 202310b5-1 | UBS Financial Services Inc. | SEC |
| Sep 25, 20234:56 PM ET | Patel SanjivDirector | 35.0K | $1.75M | Sep 25, 2023 | Morgan Stanley Smith Barney LLC Executive Services | SEC |
| Sep 19, 20234:51 PM ET | Karin WalkerOfficer | 5.00K | $261.8K | Sep 19, 202310b5-1 | Morgan Stanley Smith Barney LLC Executive Financial Services | SEC |
| Sep 13, 20234:33 PM ET | Garren HidekiOfficer | 2.00K | $110.8K | Sep 13, 202310b5-1 | UBS Financial Services, Inc. | SEC |
| Sep 13, 20234:01 PM ET | Smith Brandon S.Officer | 4.00K | $221.6K | Sep 13, 202310b5-1 | UBS Financial Services, Inc. | SEC |
| Sep 6, 20234:03 PM ET | Karp Carol D.Officer | 5.00K | $273.1K | Sep 6, 202310b5-1 | UBS Financial Services, Inc. | SEC |
| Aug 30, 20234:03 PM ET | Malecek Michael JOfficer | 5.00K | $275.1K | Aug 30, 202310b5-1 | UBS Financial Services, Inc. | SEC |
| Aug 18, 20235:23 PM ET | Karin WalkerOfficer | 5.00K | $285.9K | Aug 18, 202310b5-1 | E*TRADE FINANCIAL CORPORATION | SEC |
| Aug 16, 20234:00 PM ET | Smith Brandon S.Officer | 4.00K | $234.8K | Aug 16, 202310b5-1 | UBS Financial Services, Inc. | SEC |
| Aug 16, 20233:59 PM ET | Garren HidekiOfficer | 2.00K | $117.5K | Aug 16, 202310b5-1 | UBS Financial Services, Inc. | SEC |
| Aug 2, 20234:31 PM ET | Zago Wagner M.Officer | 4.00K | $268.2K | Aug 2, 202310b5-1 | UBS Financial Services, Inc. | SEC |
| Aug 2, 20234:17 PM ET | Karp Carol D.Officer | 5.00K | $335.1K | Aug 2, 202310b5-1 | UBS Financial Services, Inc. | SEC |
| Jul 26, 20234:01 PM ET | Malecek Michael JOfficer | 5.00K | $311.6K | Jul 26, 202310b5-1 | UBS Financial Services, Inc. | SEC |
| Jul 19, 20234:57 PM ET | Karin WalkerOfficer | 5.00K | $345.9K | Jul 19, 202310b5-1 | E*TRADE FINANCIAL CORPORATION | SEC |
| Jul 12, 20234:18 PM ET | Garren HidekiOfficer | 2.00K | $135.0K | Jul 12, 202310b5-1 | UBS Financial Services, Inc. | SEC |
| Jul 12, 20233:35 PM ET | Smith Brandon S.Officer | 4.00K | $270.0K | Jul 12, 202310b5-1 | UBS Financial Services, Inc. | SEC |
Showing the latest 25. See the PRTA notices from the last 12 months