What price ranges did the PRTA share purchases cover?

The October 7, 2026 purchases were made at prices ranging from $8.2100 to $8.6000, inclusive; the October 8, 2026 purchases ranged from $8.4000 to $8.8063, inclusive.

Prothena: William Scully’s spouse buys 125,000 shares

Q: How many PRTA shares did William P. Scully's spouse purchase?

His spouse purchased 125,000 ordinary shares on October 7, 2026, at a weighted average price of $8.4012 per share, and 90,000 shares on October 8, 2026, at a weighted average price of $8.5656 per share.

Q: What PRTA shareholdings were reported for William P. Scully?

William P. Scully was listed with 927,000 ordinary shares held directly on October 7, 2026. Manatee Equity Fund LLC was listed with 187,000 ordinary shares held indirectly on that date; Scully disclaimed beneficial ownership of those securities except to the extent of his pecuniary interest.

The ten percent owner's spouse's reported average prices reflect multiple transactions, with an execution range disclosed for each date.

Filing Impact

(Very High)

Filing Sentiment

(Positive)How Sentiment works

Sentiment and the balance of points

Rhea-AI Sentiment reads the wording of the document, how positive or negative its language is on a 1 to 5 scale. The balance of points shown with the takes weighs what the document actually discloses, so the two can disagree, for example when a trial that missed its main goal is described in upbeat language.

How Sentiment works How the balance works

Form Type

Rhea-AI Filing Summary

William P. Scully, a ten percent owner of Prothena Corp Public Ltd Co (PRTA), reported that his spouse purchased 125,000 ordinary shares on October 7, 2026, at a weighted average price of $8.4012 per share, and 90,000 shares on October 8, 2026, at a weighted average price of $8.5656 per share. The purchases comprised multiple transactions within reported ranges of $8.2100 to $8.6000 and $8.4000 to $8.8063, respectively. No Rule 10b5-1 plan is reported.

Insights

Analyzing...

Insider Trade Summary

Net Buyer: 215,000 shares

Net Buy 4 txns

Insider SCULLY WILLIAM P

Role 10% Owner

Bought 215,000 shs ($1.82M)

Type	Security	Shares	Price	Value
Purchase	Ordinary Shares, par value $0.01 per share ^F2	90,000	$8.5656	$771K
Purchase	Ordinary Shares, par value $0.01 per share ^F1	125,000	$8.4012	$1.05M
holding	Ordinary Shares, par value $0.01 per share	--	--	--
holding	Ordinary Shares, par value $0.01 per share ^F3	--	--	--

Holdings After Transaction: Ordinary Shares, par value $0.01 per share — 529,000 shares (Indirect, By Spouse); Ordinary Shares, par value $0.01 per share — 927,000 shares (Direct); Ordinary Shares, par value $0.01 per share — 187,000 shares (Indirect, By Manatee Equity Fund LLC)

Footnotes (3)

F1. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $8.2100 to $8.6000, inclusive. The reporting person undertakes to provide to Prothena Corp Public Ltd Co, any security holder of Prothena Corp Public Ltd Co, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (1) and (2) to this Form 4.
F2. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $8.4000 to $8.8063, inclusive.
F3. The reporting person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein.

Key Figures

Ordinary shares purchased by spouse: 125,000 shares Weighted average purchase price: $8.4012 per share Ordinary shares purchased by spouse: 90,000 shares +3 more

6 metrics

Ordinary shares purchased by spouse 125,000 shares October 7, 2026

Weighted average purchase price $8.4012 per share Spouse's purchases on October 7, 2026

Ordinary shares purchased by spouse 90,000 shares October 8, 2026

Weighted average purchase price $8.5656 per share Spouse's purchases on October 8, 2026

Ordinary shares held directly 927,000 shares Reported holding on October 7, 2026

Ordinary shares held by Manatee Equity Fund LLC 187,000 shares Indirect holding reported on October 7, 2026; William P. Scully disclaims beneficial ownership except to the extent of his pecuniary interest.

Key Terms

weighted average price, pecuniary interest, Ordinary Shares

3 terms

weighted average price financial

"The price reported in Column 4 is a weighted average price."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

pecuniary interest financial

"except to the extent of his pecuniary interest therein"

Ordinary Shares financial

"Ordinary Shares, par value $0.01 per share"

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.

How many PRTA shares did William P. Scully's spouse purchase?

His spouse purchased 125,000 ordinary shares on October 7, 2026, at a weighted average price of $8.4012 per share, and 90,000 shares on October 8, 2026, at a weighted average price of $8.5656 per share.

What PRTA shareholdings were reported for William P. Scully?

William P. Scully was listed with 927,000 ordinary shares held directly on October 7, 2026. Manatee Equity Fund LLC was listed with 187,000 ordinary shares held indirectly on that date; Scully disclaimed beneficial ownership of those securities except to the extent of his pecuniary interest.

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

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Available on EDGAR 10/09/2026 - 09:43 AM Accepted by SEC EDGAR 10/09/2026 - 09:43 AM

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^*

SCULLY WILLIAM P

(Last)

(First)

(Middle)

771 MANATEE COVE

(Street)

VERO BEACH

FLORIDA

32963

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
10/07/2026

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Ordinary Shares, par value $0.01 per share	10/07/2026		P		125,000	A	$8.4012⁽¹⁾	439,000	I	By Spouse
Ordinary Shares, par value $0.01 per share	10/08/2026		P		90,000	A	$8.5656⁽²⁾	529,000	I	By Spouse
Ordinary Shares, par value $0.01 per share								927,000	D
Ordinary Shares, par value $0.01 per share								187,000	I	By Manatee Equity Fund LLC⁽³⁾

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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

Explanation of Responses:

1. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $8.2100 to $8.6000, inclusive. The reporting person undertakes to provide to Prothena Corp Public Ltd Co, any security holder of Prothena Corp Public Ltd Co, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (1) and (2) to this Form 4.

2. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $8.4000 to $8.8063, inclusive.

3. The reporting person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein.

	Reid E. Buchanan by POA from William P. Scully	10/09/2026
	** 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)

Source: View Original Filing on SEC EDGAR