Prothena director granted options on 27,000 shares

PROTHENA CORP PUBLIC LTD CO director William H. Dunn Jr. received a grant of stock options covering 27,000 ordinary shares.

Accepted by SEC EDGAR 05/15/2026 - 09:28 PM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

PROTHENA CORP PUBLIC LTD CO director William H. Dunn Jr. received a grant of stock options covering 27,000 ordinary shares. The options have an exercise price of $9.76 per share, expire on May 15, 2036, and will vest 100% on the earlier of the first anniversary of the grant date or the company’s 2027 annual general meeting, assuming continuous board service.

Insider Trade Summary

Grant/Award: 27,000 shares

Grant/Award 1 txn

Insider Dunn William H. Jr.

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Stock Option (Right to Buy)	27,000	$0.00	$0.00

Holdings After Transaction: Stock Option (Right to Buy) — 27,000 contracts (Direct)

Footnotes (1)

1. F1. The shares subject to the option will vest and become exercisable as to 100% of the total number of shares subject to the option on the earlier of the first anniversary of the grant date or the day of the annual general meeting in 2027 of the Issuer's shareholders, assuming continuous service as a director until such vesting date.

Key Figures

Option grant size: 27,000 shares Exercise price: $9.76 per share Underlying shares: 27,000 shares +2 more

5 metrics

Option grant size 27,000 shares Stock Option (Right to Buy) granted to director

Exercise price $9.76 per share Conversion or exercise price of granted options

Underlying shares 27,000 shares Ordinary Shares underlying the option grant

Expiration date May 15, 2036 Option expiration for director’s grant

Post-grant derivative holdings 27,000 options Total derivative securities following transaction

Key Terms

Stock Option (Right to Buy), Grant, award, or other acquisition, Ordinary Shares, vest and become exercisable

4 terms

Stock Option (Right to Buy) financial

"security_title: "Stock Option (Right to Buy)""

Grant, award, or other acquisition financial

"transaction_code_description: "Grant, award, or other acquisition""

Ordinary Shares financial

"underlying_security_title: "Ordinary Shares""

Ordinary shares are a type of ownership stake in a company, giving shareholders a right to participate in the company’s profits and decision-making through voting. They are similar to owning a piece of a business, and their value can rise or fall based on the company's performance. Investors buy ordinary shares to potentially earn dividends and benefit from the company's growth over time.

vest and become exercisable financial

"The shares subject to the option will vest and become exercisable as to 100% of the total number of shares"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transaction did Prothena (PRTA) disclose for William H. Dunn Jr.?

Prothena disclosed that director William H. Dunn Jr. received a grant of stock options for 27,000 ordinary shares. These options were awarded as a compensation-related grant, not an open-market purchase or sale, and are exercisable at a fixed price once fully vested.

How many Prothena (PRTA) shares are covered by William H. Dunn Jr.’s new options?

The option grant to William H. Dunn Jr. covers 27,000 underlying ordinary shares of Prothena. All 27,000 shares are tied to a single option award that vests in full on a future date, subject to his continued service as a director until that vesting date.

What is the exercise price and expiration date of William H. Dunn Jr.’s Prothena options?

The granted options have an exercise price of $9.76 per Prothena ordinary share and an expiration date of May 15, 2036. This means Dunn can buy shares at $9.76 any time after vesting and before that expiration, subject to the plan’s terms.

When do William H. Dunn Jr.’s Prothena stock options vest?

The options will vest and become exercisable for 100% of the 27,000 shares on the earlier of the first anniversary of the grant date or the day of Prothena’s 2027 annual general meeting, assuming Dunn continuously serves as a director through that vesting date.

Is William H. Dunn Jr.’s Prothena Form 4 transaction a market buy or sell?

The Form 4 reports a grant of stock options, coded as a grant, award, or other acquisition, not a market purchase or sale. It reflects compensation in the form of options rather than Dunn buying or selling Prothena shares in the open market.

AI-generated analysis. How Rhea-AI works. Not financial advice.

Form 4 Insider Transactions: What Each Field Means →

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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
Estimated average burden
hours per response:			0.5

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^*

Dunn William H. Jr.

(Last) (First) (Middle)

C/O PROTHENA BIOSCIENCES INC

1800 SIERRA POINT PARKWAY

(Street)

BRISBANE CALIFORNIA 94005

(City) (State) (Zip)

UNITED STATES

(Country)

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)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/15/2026

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

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

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

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

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
Stock Option (Right to Buy)	$9.76	05/15/2026		A		27,000		(1)	05/15/2036	Ordinary Shares	27,000	$0	27,000	D

Explanation of Responses:

1. The shares subject to the option will vest and become exercisable as to 100% of the total number of shares subject to the option on the earlier of the first anniversary of the grant date or the day of the annual general meeting in 2027 of the Issuer's shareholders, assuming continuous service as a director until such vesting date.

	/s/ Michael J. Malecek, as Attorney-in-Fact for William H. Dunn Jr.	05/15/2026
	** 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.
* Form 4: SEC 1474 (03-26)