[Form 4] Prothena Corporation plc Insider Trading Activity

Rhea-AI Filing Summary

On 28 Jul 2025, Prothena Corporation plc (PRTA) filed a Form 4 reporting that its Chief Scientific Officer, Dr. Wagner M. Zago, acquired 85,000 ordinary shares of the company. The transaction was coded “A,” indicating an acquisition that was not purchased for cash (reported price $0), consistent with an equity award or similar grant. Following the transaction, Dr. Zago’s direct beneficial ownership totals 85,000 shares. No derivative securities were reported, and there were no dispositions. The filing was signed by Michael J. Malecek under power of attorney on 30 Jul 2025.

Positive

• 85,000-share equity award increases insider ownership and may strengthen management-shareholder alignment.

Negative

• None.

Insights

Corporate Governance Analyst

TL;DR: Routine equity grant; increases insider alignment, limited immediate market impact.

The Form 4 shows a one-time, zero-cost award of 85,000 ordinary shares to Prothena’s CSO. Because no cash changed hands and there is no indication of an open-market purchase, the event appears to be a standard incentive grant. Such issuances modestly enhance insider ownership, which can be viewed positively from an alignment standpoint, but they generally have neutral valuation impact given their pre-planned nature and small potential dilution relative to total shares outstanding. No negative governance red flags are apparent.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Zago Wagner M.

(Last) (First) (Middle)

C/O PROTHENA BIOSCIENCES INC

1800 SIERRA POINT PARKWAY

(Street)

BRISBANE CA 94005

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
PROTHENA CORP PUBLIC LTD CO [ PRTA ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Scientific Officer

3. Date of Earliest Transaction (Month/Day/Year)
07/28/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Ordinary Shares, par value $0.01 per share	07/28/2025		A		85,000	A	$0	85,000	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

	/s/ Michael J. Malecek, as Attorney-in-Fact for Wagner M. Zago	07/30/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

How many PRTA shares did the CSO acquire?

85,000 ordinary shares were acquired on 28 Jul 2025.

Was cash paid for the shares?

No. The reported price was $0, indicating an equity grant rather than a purchase.

What is Dr. Zago's total PRTA ownership after the transaction?

He now directly owns 85,000 shares.

Were any derivative securities involved?

No derivative securities were reported in Table II.

When was the Form 4 signed and filed?

The filing was signed on 30 Jul 2025 and covers a transaction dated 28 Jul 2025.