Prothena CDO exercises 51,000 RSUs, withholds shares

PROTHENA CORP PUBLIC LTD CO Chief Development Officer Chad J. Swanson exercised 51,000 restricted stock units into the same number of ordinary shares on July 28, 2026.

Accepted by SEC EDGAR 07/30/2026 - 08:33 PM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

PROTHENA CORP PUBLIC LTD CO Chief Development Officer Chad J. Swanson exercised 51,000 restricted stock units into the same number of ordinary shares on July 28, 2026. On the same date he returned 40,800 shares to the issuer and had 3,467 shares withheld at $8.56 per share to pay the exercise price or tax liabilities. These RSUs were part of an 85,000‑unit grant made July 28, 2025, of which 34,000 RSUs remain subject to vesting.

Insider Trade Summary

51,000 shares exercised/converted

Exercise 4 txns

Insider Swanson Chad J.

Role Chief Development Officer

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Units F2, F1, F3	51,000	$0.00	$0.00
Exercise	Ordinary Shares, par value $0.01 per share F1	51,000	--	--
Disposition	Ordinary Shares, par value $0.01 per share	40,800	$8.56	$349K
Exercise Price or Tax Liability	Ordinary Shares, par value $0.01 per share	3,467	$8.56	$30K

Holdings After Transaction: Restricted Stock Units — 0 contracts (Direct); Ordinary Shares, par value $0.01 per share — 40,733 shares (Direct)

Footnotes (3)

1. F1. Each restricted stock unit ("RSU") represents the contingent right to receive one share of the Issuer's Ordinary Shares upon vesting.
2. F2. These RSUs reported in Table II were granted to the Reporting Person on July 28, 2025 as part of an aggregate award of 85,000 RSUs and initially reported in Table I of the Form 4 filed on July 30, 2025, because they were solely settleable in shares at the time of grant. These RSUs are being moved to Table II as of this Form 4.
3. F3. These RSUs reported in Table II are fully vested as of July 28, 2026 (the one-year anniversary of the grant date). The remainder of the 85,000 RSUs reported in Table I (34,000 RSUs) are subject to vesting.

Key Figures

RSUs exercised: 51,000 units Shares disposed to issuer: 40,800 shares Shares withheld for obligations: 3,467 shares +3 more

6 metrics

RSUs exercised 51,000 units Restricted Stock Units converted into ordinary shares on July 28, 2026

Shares disposed to issuer 40,800 shares Ordinary shares returned to issuer at $8.56 per share

Shares withheld for obligations 3,467 shares Withheld at $8.56 per share to pay exercise price or tax liability

Share price for dispositions $8.56 per share Applied to both shares returned to issuer and shares withheld

Original RSU grant size 85,000 RSUs Grant awarded to Chad J. Swanson on July 28, 2025

Unvested RSUs remaining 34,000 RSUs Portion of the 85,000‑unit grant still subject to vesting

Key Terms

Restricted Stock Units, Disposition to issuer, Payment of exercise price or tax liability, Ordinary Shares

4 terms

Restricted Stock Units financial

"Each restricted stock unit ("RSU") represents the contingent right to receive one share"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

Disposition to issuer financial

"transaction_code_description": "Disposition to issuer""

Payment of exercise price or tax liability financial

"transaction_code_description": "Payment of exercise price or tax liability by delivering"

Ordinary Shares financial

"one share of the Issuer's Ordinary Shares upon vesting"

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.

FAQ

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

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

Prothena reported that Chief Development Officer Chad J. Swanson exercised 51,000 RSUs into ordinary shares on July 28, 2026, then returned 40,800 shares to the issuer and had 3,467 shares withheld at $8.56 per share to satisfy exercise-price or tax obligations.

How many Prothena (PRTA) RSUs vested for Chad J. Swanson and what grant were they from?

On July 28, 2026, 51,000 RSUs fully vested for Chad J. Swanson. They came from an 85,000‑RSU grant awarded on July 28, 2025. According to the disclosure, 34,000 RSUs from that grant remain unvested and subject to future vesting conditions.

At what price were Prothena (PRTA) shares returned or withheld in Chad J. Swanson’s Form 4?

The filing shows ordinary shares were returned to Prothena and withheld at a price of $8.56 per share. This price applied to the 40,800 shares disposed to the issuer and the 3,467 shares withheld for exercise-price or tax-liability purposes.

Did Chad J. Swanson’s Prothena (PRTA) Form 4 involve tax or exercise-price share withholding?

Yes. The Form 4 reports a code F transaction where 3,467 ordinary shares were withheld at $8.56 per share. The description specifies this as a payment of exercise price or tax liability by delivering or withholding Prothena securities.

How many Prothena (PRTA) RSUs from Chad J. Swanson’s 2025 grant remain unvested?

From the original 85,000‑RSU grant dated July 28, 2025, the company states that 34,000 RSUs remain subject to vesting. The other 51,000 RSUs reported in the filing are fully vested and were converted into ordinary shares.

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

Form 4 Insider Transactions: What Each Field Means →

See more from StockTitan in Google Search and AI answers. Adds StockTitan as a preferred source · opens Google

Add on Google Not now

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 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)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
07/28/2026

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
Ordinary Shares, par value $0.01 per share	07/28/2026		M		51,000	A	(1)	85,000	D
Ordinary Shares, par value $0.01 per share	07/28/2026		D		40,800	D	$8.56	44,200	D
Ordinary Shares, par value $0.01 per share	07/28/2026		F		3,467	D	$8.56	40,733	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
Restricted Stock Units(2)	(1)	07/28/2026		M			51,000	(3)	(3)	Ordinary Shares	51,000	$0	0	D

Explanation of Responses:

1. Each restricted stock unit ("RSU") represents the contingent right to receive one share of the Issuer's Ordinary Shares upon vesting.

2. These RSUs reported in Table II were granted to the Reporting Person on July 28, 2025 as part of an aggregate award of 85,000 RSUs and initially reported in Table I of the Form 4 filed on July 30, 2025, because they were solely settleable in shares at the time of grant. These RSUs are being moved to Table II as of this Form 4.

3. These RSUs reported in Table II are fully vested as of July 28, 2026 (the one-year anniversary of the grant date). The remainder of the 85,000 RSUs reported in Table I (34,000 RSUs) are subject to vesting.

	/s/ Michael J. Isaacs, as Attorney-in-Fact for Chad J. Swanson	07/30/2026
	** 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)