Prothena (PRTA) CDO awarded 190,000 stock options grant

Rhea-AI Filing Summary

PROTHENA CORP PUBLIC LTD CO reported that Chief Development Officer Chad J. Swanson acquired a grant of 190,000 stock options on March 3, 2026. The options were awarded at no cost as a “Stock Option (Right to Buy).”

According to the vesting terms, 25% of the total options will vest and become exercisable on March 3, 2027. The remaining options will vest in equal monthly installments of 1/48th of the total number of shares on each monthly anniversary thereafter, subject to his continued employment with the company on each vesting date.

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^*

Swanson Chad J.

(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 Development Officer

3. Date of Earliest Transaction (Month/Day/Year)
03/03/2026

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

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)	$9.36	03/03/2026		A		190,000		(1)	03/03/2036	Ordinary Shares	190,000	$0	190,000	D

Explanation of Responses:

1. The shares subject to the option will vest and become exercisable as to 25% of the total number of shares subject to the option on March 3, 2027, and with respect to 1/48th of the total number of shares subject to the option in successive, equal monthly installments on each monthly anniversary thereafter, subject to the Reporting Person's continued employment with the Issuer on each such vesting date.

	/s/ Michael Malecek, as Attorney in Fact for Chad J. Swanson	03/05/2026
	** 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.

FAQ

What insider transaction did Prothena (PRTA) report for Chad J. Swanson?

Prothena reported that Chief Development Officer Chad J. Swanson received a grant of 190,000 stock options. These options are classified as a “Stock Option (Right to Buy)” and were awarded on March 3, 2026, increasing his directly held derivative securities to 190,000.

How many Prothena (PRTA) stock options were granted to the CDO?

Chad J. Swanson was granted 190,000 stock options. This entire amount represents a new award, bringing his total stock options following the transaction to 190,000, according to the Form 4 derivative transaction table for PROTHENA CORP PUBLIC LTD CO.

What is the vesting schedule for Chad J. Swanson’s 190,000 Prothena options?

The option grant vests 25% of the total shares on March 3, 2027. The remaining options vest in 1/48th monthly installments on each monthly anniversary thereafter, contingent on his continued employment with Prothena on each vesting date.

Is Chad J. Swanson’s Prothena stock option grant a direct or indirect holding?

The Form 4 classifies the 190,000 stock options as a direct holding. The ownership code is listed as “D” for direct, and no footnote indicates any trust, LLC, or other entity holding these derivative securities on his behalf.

Does the Form 4 for Prothena (PRTA) show any insider stock sales?

The Form 4 shows only an acquisition of derivative securities, not any sales. It reports one grant of 190,000 stock options coded as an acquisition (transaction code A), with no corresponding sell or dispose transactions in the summarized insider activity.