Prothena Corp Public Ltd Co (PRTA) discloses executive share sales and tax withholding

Rhea-AI Filing Summary

Prothena Corp Public Ltd Co Chief Strategy Officer Anne Evans Kingston reported selling 7,662 ordinary shares on July 29, 2026 at a weighted average price of $8.4729, in multiple trades between $8.40 and $8.64, under a Rule 10b5-1 trading plan adopted on March 30, 2026. On July 28, 2026, 3,498 shares were disposed of at $8.56 per share to satisfy tax obligations by delivering or withholding securities.

Insider Trade Summary 10b5-1

Net Seller: 11,160 shares

Net Sell 2 txns

Insider Kingston Anne Evans

Role Chief Strategy Officer

Sold 7,662 shs ($65K)

Type	Security	Shares	Price	Value
Sale	Ordinary Shares, par value $0.01 per share F1, F2	7,662	$8.4729	$65K
Exercise Price or Tax Liability	Ordinary Shares, par value $0.01 per share	3,498	$8.56	$30K

Holdings After Transaction: Ordinary Shares, par value $0.01 per share — 55,782 shares (Direct)

Footnotes (2)

1. F1. The transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on March 30, 2026.
2. F2. The transaction was executed in multiple trades in prices ranging from $8.40 to $8.64, 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 ranges set forth in this footnote.

Key Figures

Shares sold: 7,662 shares Sale price (weighted avg): $8.4729 per share Price range of trades: $8.40–$8.64 per share +3 more

6 metrics

Shares sold 7,662 shares Open-market sale of ordinary shares on July 29, 2026

Sale price (weighted avg) $8.4729 per share Average price for shares sold on July 29, 2026

Price range of trades $8.40–$8.64 per share Range of execution prices for July 29, 2026 sale

Shares withheld for tax 3,498 shares Disposition on July 28, 2026 to cover tax or exercise obligations

Tax disposition price $8.56 per share Price for shares delivered/withheld on July 28, 2026

Rule 10b5-1 plan adoption March 30, 2026 Adoption date for trading plan governing the July 29, 2026 sale

Key Terms

Rule 10b5-1 trading plan, weighted average sale price, Ordinary Shares, par value $0.01 per share, tax liability

4 terms

Rule 10b5-1 trading plan regulatory

"pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

weighted average sale price financial

"The price reported in Column 4 above reflects the weighted average sale price"

Ordinary Shares, par value $0.01 per share financial

"Ordinary Shares, par value $0.01 per share"

tax liability financial

"Payment of exercise price or tax liability by delivering or withholding securities"

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 07/30/2026 - 08:31 PM Accepted by SEC EDGAR 07/30/2026 - 08:31 PM Learn about SEC filing dates

FAQ

What insider transactions did Prothena (PRTA) report for Anne Evans Kingston?

Anne Evans Kingston reported two transactions. She sold 7,662 ordinary shares on July 29, 2026 at a weighted average price of $8.4729, and on July 28, 2026 had 3,498 shares disposed of at $8.56 per share to satisfy tax obligations.

At what prices were the Prothena (PRTA) insider share sales executed?

The main sale involved 7,662 shares at a weighted average price of $8.4729, with individual trades between $8.40 and $8.64. A separate tax-related disposition of 3,498 shares occurred at a price of $8.56 per share.

Were the recent Prothena (PRTA) insider sales made under a Rule 10b5-1 plan?

Yes. The reported sale of 7,662 ordinary shares on July 29, 2026 was effected pursuant to a Rule 10b5-1 trading plan adopted by Anne Evans Kingston on March 30, 2026. This indicates the sale followed a pre-arranged trading schedule.

What portion of Prothena (PRTA) insider activity related to taxes for Anne Evans Kingston?

One transaction involved 3,498 shares on July 28, 2026 coded as an F transaction, meaning shares were delivered or withheld to pay an exercise price or tax liability. This is separate from the open-market sale of 7,662 shares.

What type of security did Prothena (PRTA) executive Anne Evans Kingston trade?

Both transactions involved Prothena’s Ordinary Shares, par value $0.01 per share. She sold 7,662 shares in an open-market sale and had 3,498 shares delivered or withheld to satisfy tax-related obligations tied to equity compensation.

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).

X

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^*

Kingston Anne Evans

(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 Strategy 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		F		3,498	D	$8.56	63,444	D
Ordinary Shares, par value $0.01 per share	07/29/2026		S(1)		7,662	D	$8.4729(2)	55,782	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:

1. The transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on March 30, 2026.

2. The transaction was executed in multiple trades in prices ranging from $8.40 to $8.64, 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 ranges set forth in this footnote.

	/s/ Michael J. Isaacs, as Attorney-in-Fact for Anne E. Kingston	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)