Wednesday, October 28, 2026
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Public filings, plainly told
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PRTA Insider Trading and Fund Holdings (PROTHENA CORP PUBLIC LTD CO) · https://wallstpal.com/stock/prta/ · saved 2026-10-28

About this page

Insider trades reported on SEC Form 4: when the people who run a company buy or sell its shares with their own money.

How to read it

Form 4
The form a company insider (officer, director or owner of more than 10%) must file with the SEC within two business days of buying or selling the company's shares.
Buy (P) and Sell (S)
Open-market purchases and sales. Gifts, option exercises and automatic tax withholding are left out because they say little about what the insider thinks.
Value
Shares times price, as reported on the filing.
10b5-1
A trade made under a plan set up in advance. Planned sales are common and usually say less than an unplanned purchase.
Late filing
A Form 4 filed more than two business days after the trade.
Vs. S&P 500
How the stock did after the trade minus how the overall market did in the same weeks.

A real example

In January 2016, when bank stocks were falling, JPMorgan Chase CEO Jamie Dimon bought 500,000 JPMorgan shares with his own money, worth about $26 million. His Form 4 made the purchase public within days, and investors read it as a strong sign of confidence.

Explain it like I'm 13

If the coach of a team bets his own allowance that his team will win, that tells you something. A Form 4 is the note a company boss must hand in whenever he buys or sells his own company's shares, so everyone can see it.

Data from public SEC filings and congressional reports. Information, not investment advice. Check every number against the filing linked on the page.

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StockCIK 1559053

PROTHENA CORP PUBLIC LTD CO (PRTA): Insider Trades and Fund Holdings

In the past 12 months, PROTHENA CORP PUBLIC LTD CO insiders reported 15 open-market purchases worth $9.14M and 2 sales worth $136K; 2 of the sales were reported as made under a 10b5-1 trading plan.

15Insider buys, 12 months
$9.14MBought by insiders, 12 months
$136KSold by insiders, 12 months
1Tracked funds holding

Timeline: news and trades

Company filings (8-K), insider trades, notices of planned sales (Form 144), Congress trades and fund moves in the past year, newest first.

  1. Oct 23, 2026Insider buy10% owner William P. Scully bought $403,525
  2. Oct 22, 2026Insider buy10% owner William P. Scully bought $818,520
  3. Oct 14, 2026Insider buy10% owner William P. Scully bought $84,569
  4. Oct 13, 2026Insider buy10% owner William P. Scully bought $835,480
  5. Oct 8, 2026Insider buy10% owner William P. Scully bought $770,904 (6 days after: executive or director change)
  6. Oct 7, 2026Insider buy10% owner William P. Scully bought $1.1 million (5 days after: executive or director change)
  7. Oct 2, 2026NewsCompany reported: Executive or director change
  8. Oct 2, 2026Insider buy10% owner William P. Scully bought $857,240 (0 days after: executive or director change)
  9. Sep 29, 2026Insider buy10% owner William P. Scully bought $1.4 million
  10. Sep 28, 2026Insider buy10% owner William P. Scully bought $889,872
  11. Sep 18, 2026Insider buy10% owner William P. Scully bought $843,460
  12. Sep 2, 2026Insider buy10% owner William P. Scully bought $255,739
  13. Aug 20, 2026Insider buy10% owner William P. Scully bought $439,430
  14. Aug 7, 2026Insider buy10% owner William P. Scully bought $323,220 (1 days after: quarterly or annual results)
  15. Aug 6, 2026NewsCompany reported: Quarterly or annual results
  16. Jul 29, 2026Insider saleGeneral Counsel Michael John Isaacs sold $71,055 under a 10b5-1 plan
  17. Jul 29, 2026Insider saleChief Strategy Officer Anne Evans Kingston sold $64,919 under a 10b5-1 plan
  18. Jul 29, 2026Planned saleMICHAEL JOHN ISAACS (officer) filed notice to sell about $71,055 around Jul 29, 2026
  19. Jul 29, 2026Planned saleANNE KINGSTON (officer) filed notice to sell about $64,919 around Jul 29, 2026
  20. Jun 30, 2026FundRenaissance Technologies added 15% in Q2 2026 (13F filed Aug 13, 2026)
  21. Jun 16, 2026Insider buy10% owner William P. Scully bought $157,990

Recent insider trades

Open-market purchases (code P) and sales (code S) from Form 4. Grants, option exercises and gifts are not shown. Latest filing: Oct 26, 2026.

Recent PRTA insider trades
FiledTradedInsiderRoleTypeSharesPrice ($)ValueScoreHoldingFiling
Oct 26Oct 22William P. Scully10% owner10% owner▲ BUY100,0008.19$819K23+9.6%Form 4 ↗
Oct 26Oct 23William P. Scully10% owner10% owner▲ BUY50,0008.07$404K15+4.4%Form 4 ↗
Oct 15Oct 13William P. Scully10% owner10% owner▲ BUY100,0008.35$835K27+11%Form 4 ↗
Oct 15Oct 14William P. Scully10% owner10% owner▲ BUY10,0008.46$85K10+1.0%Form 4 ↗
Oct 9Oct 7William P. Scully10% owner10% owner (ind.)▲ BUY125,0008.40$1.05M35+40%Form 4 ↗
Oct 9Oct 8William P. Scully10% owner10% owner (ind.)▲ BUY90,0008.57$771K32+21%Form 4 ↗
Oct 6Oct 2William P. Scully10% owner10% owner (ind.)▲ BUY100,0008.57$857K39+47%Form 4 ↗
Sep 30Sep 29William P. Scully10% owner10% owner (ind.)▲ BUY162,0008.68$1.41M47+312%Form 4 ↗
Sep 29Sep 28William P. Scully10% owner10% owner (ind.)▲ BUY103,5008.60$890K44+124%Form 4 ↗
Sep 21Sep 18William P. Scully10% owner10% owner▲ BUY100,0008.43$843K27+12%Form 4 ↗
Source: SEC Form 4 filings, retrieved Oct 28, 2026. How we read filings
All 17 PRTA insider trades →

Insiders who traded in the past year

InsiderRoleBuysBoughtSellsSoldLatest
William P. Scully10% owner15$9.14M0$0Oct 26, 2026
Michael John IsaacsGeneral Counsel0$01$71KJul 30, 2026
Anne Evans KingstonChief Strategy Officer0$01$65KJul 30, 2026
Strongest purchase, 12 months

47 William P. Scully (10% owner), 2026-09-29. What the score means

Filing quality

A All 17 insider trades reported on time. How it is graded

Tracked funds that report PRTA

From each fund's latest 13F. Holdings are as of quarter end and are filed up to 45 days later.

FundQuarterSharesValue% of portfolioChange
Renaissance TechnologiesQ2 2026697,615$6.83M0.01%▲ +14.8%
Source: SEC Form 13F-HR filings, retrieved Oct 28, 2026. How we read filings

Reading these numbers

Insiders sell for many reasons: taxes, diversification, a house. Purchases with their own money are rarer and are usually read as more informative. A Form 4 is due within two business days of the trade. How to read a Form 4 →