Michael J. Isaacs - 28 Jul 2026 Form 4 Insider Report for PROTHENA CORP PUBLIC LTD CO (PRTA)

Reporting relationship: General Counsel & Company Sec.
Issuer ticker: PRTA
Reported as of: 28 Jul 2026
Net transaction value: -$71,055
SEC form: 4
Accepted by SEC: 30 Jul 2026, 20:30:22 UTC
Prior SEC filing: 12 Jun 2026
Source filing: View source filing
Reporting owner signature: /s/ Michael J. Isaacs

Key filing fact

Michael J. Isaacs filed Form 4 for PROTHENA CORP PUBLIC LTD CO (PRTA) on 30 Jul 2026.

Key facts

This page summarizes Michael J. Isaacs's Form 4 filing for PROTHENA CORP PUBLIC LTD CO (PRTA).
2 reported transactions and 0 derivative rows are listed below.
Accepted by SEC: 30 Jul 2026, 20:30.

Change

Previous filing in this sequence was filed on 12 Jun 2026.
Current net transaction value: -$71,055.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0002127815 Primary reporting owner

Isaacs Michael John

Relationship: General Counsel & Company Sec.
Address: C/O PROTHENA BIOSCIENCES INC., 1800 SIERRA POINT PARKWAY, BRISBANE
Signature: /s/ Michael J. Isaacs
Signature date: 30 Jul 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

PRTA transaction

Ordinary Shares, par value $0.01 per share

Tax liability

Transaction value
Shares: -4,694
Change %: -9.6%
Price: $8.56^*
Shares after: 44,131
Date: 28 Jul 2026
Ownership: Direct

PRTA transaction

Ordinary Shares, par value $0.01 per share

Sale

Transaction value: $71,055
Shares: -8,386
Change %: -19%
Price: $8.47
Shares after: 35,745
Date: 29 Jul 2026
Ownership: Direct
Footnotes: F1, F2

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Rule 10b5-1 trading plan

These transactions were reported as open-market trades under a Rule 10b5-1 plan. The plan lets an insider set trading instructions in advance, which can reduce the risk of trading while in possession of material nonpublic information.

Original filing language: transaction made pursuant to a contract, instruction, or written plan intended to satisfy Rule 10b5-1(c).

Explanation of responses 2 footnotes

Footnote F1

The transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on April 3, 2026.

Footnote F2

The transaction was executed in multiple trades in prices ranging from $8.40 to $8.65, inclusive. The price reported in Column 4 above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares sold at each respective price within the range set forth in this footnote.