Prothena (PRTA) large holder Todd Fennell reports 5.0M-share, 9.76% stake

Rhea-AI Filing Summary

Todd W. Fennell reports beneficial ownership of 5,010,846 Ordinary Shares of Prothena Corp Public Ltd Co, held entirely through various trusts where he serves as independent trustee. These shares represent approximately 9.76% of Prothena’s Ordinary Shares outstanding, based on 51,336,974 shares outstanding as of July 30, 2026.

All 5,010,846 shares are subject to shared voting and shared dispositive power, with no sole voting or dispositive authority reported. The filing states that Fennell disclaims beneficial ownership of any Ordinary Shares in which he does not have a pecuniary interest and expressly disclaims any status as part of a group with any other party.

Key Figures

Beneficially owned shares: 5,010,846 Ordinary Shares Ownership percentage: 9.76% Shares outstanding: 51,336,974 Ordinary Shares +4 more

7 metrics

Beneficially owned shares 5,010,846 Ordinary Shares Shares that Todd W. Fennell may be deemed to beneficially own

Ownership percentage 9.76% Approximate percent of Prothena Ordinary Shares beneficially owned

Shares outstanding 51,336,974 Ordinary Shares Shares outstanding as of July 30, 2026, per Prothena’s Form 10-Q

Trust-held shares 215,000 Ordinary Shares Shares held by various trusts with Fennell as independent trustee

GRAT-held shares 4,795,846 Ordinary Shares Shares held by various grantor retained annuity trusts

Shared voting power 5,010,846 Ordinary Shares Shares over which Fennell reports shared voting power

Shared dispositive power 5,010,846 Ordinary Shares Shares over which Fennell reports shared dispositive power

Key Terms

beneficial owner, grantor retained annuity trusts, pecuniary interest, shared dispositive power, +1 more

5 terms

beneficial owner financial

"The Reporting Person may be deemed to be the beneficial owner of 5,010,846 Ordinary Shares."

A beneficial owner is the person who ultimately owns or controls a financial asset or property, even if their name isn't directly on official documents. Think of it like someone who secretly holds the keys to a safe deposit box—others may appear to have access, but the true owner is the one who benefits from what's inside. Identifying beneficial owners helps ensure transparency and prevent illegal activities like money laundering or fraud.

grantor retained annuity trusts financial

"4,795,846 Ordinary Shares owned in the aggregate by various grantor retained annuity trusts"

A grantor retained annuity trust (GRAT) is an estate-planning tool where an owner transfers assets into a trust and receives fixed payments back for a set number of years; any remaining assets after that period pass to designated beneficiaries. For investors it matters because it can move future investment growth to heirs while potentially reducing gift and estate taxes — like putting a rising asset in a timed box that pays you first and gives the remaining upside to others.

pecuniary interest financial

"disclaims beneficial ownership of all Ordinary Shares to which the Reporting Person does not have a pecuniary interest"

shared dispositive power financial

"Shared Dispositive Power 5,010,846.00"

shared voting power financial

"Shared Voting Power 5,010,846.00"

Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.

FAQ

What percentage of Prothena (PRTA) does Todd W. Fennell report owning?

Todd W. Fennell reports beneficial ownership of approximately 9.76% of Prothena’s Ordinary Shares. This is based on 5,010,846 shares compared with 51,336,974 shares outstanding as of July 30, 2026.

How many Prothena (PRTA) shares does Todd W. Fennell beneficially own?

Todd W. Fennell may be deemed to beneficially own 5,010,846 Ordinary Shares of Prothena. These consist of 215,000 shares held by various trusts and 4,795,846 shares held by grantor retained annuity trusts.

Does Todd W. Fennell have sole voting power over his Prothena (PRTA) holdings?

No. The filing reports 0 shares with sole voting power and 5,010,846 shares with shared voting power. He also has shared, but not sole, dispositive power over the same 5,010,846 shares.

How many Prothena (PRTA) shares were outstanding for this ownership calculation?

The ownership percentage is calculated using 51,336,974 Ordinary Shares outstanding as of July 30, 2026, as stated in Prothena’s most recent Quarterly Report for the quarter ended June 30, 2026.

How are Todd W. Fennell’s Prothena (PRTA) shares held?

The 5,010,846 shares are held through trusts where he serves as independent trustee: 215,000 shares in various trusts and 4,795,846 shares in grantor retained annuity trusts, all with shared voting and dispositive power.

Does Todd W. Fennell disclaim any beneficial ownership of Prothena (PRTA) shares?

Yes. He disclaims beneficial ownership of all Ordinary Shares in which he does not have a pecuniary interest and expressly disclaims any status as a group with any other party.

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

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Available on EDGAR 08/14/2026 - 09:10 AM Accepted by SEC EDGAR 08/14/2026 - 09:10 AM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 6)

PROTHENA CORP PUBLIC LTD CO

(Name of Issuer)

Ordinary Shares, $0.01 par value

(Title of Class of Securities)

G72800108

(CUSIP Number)

06/30/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): G72800108

1

Names of Reporting Persons

Fennell Todd W.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

FLORIDA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 5,010,846.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 5,010,846.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

5,010,846.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

9.8 %

12

Type of Reporting Person (See Instructions)

IN

Comment for Type of Reporting Person: See Item 4

SCHEDULE 13G

Item 1.
(a)	Name of issuer: PROTHENA CORP PUBLIC LTD CO
(b)	Address of issuer's principal executive offices: 77 SIR JOHN ROGERSON'S QUAY, BLOCK C, GRAND CANAL DOCKLANDS, DUBLIN 2, IRELAND, D02 VK60.
Item 2.
(a)	Name of person filing: Todd W. Fennell
(b)	Address or principal business office or, if none, residence: 979 Beachland Boulevard, Vero Beach Florida, 32963
(c)	Citizenship: Florida
(d)	Title of class of securities: Ordinary Shares, $0.01 par value
(e)	CUSIP No.: G72800108
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: The Reporting Person may be deemed to be the beneficial owner of 5,010,846 Ordinary Shares. This amount consists of (i) 215,000 owned by various trusts, for which the Reporting Person serves as an independent trustee, and (ii) 4,795,846 Ordinary Shares owned in the aggregate by various grantor retained annuity trusts, for which the Reporting Person serves as an independent trustee.
(b)	Percent of class: According to the Issuers most recent Quarterly Report on Form 10-Q for the quarter ended June 30, 2026, the number of shares outstanding as of July 30, 2026 was 51,336,974. The Ordinary Shares which the Reporting Person may be deemed to beneficially own constitute approximately 9.76% of such total number of shares. The Reporting Person disclaims beneficial ownership of all Ordinary Shares to which the Reporting Person does not have a pecuniary interest, and the Reporting Person expressly disclaims any status as a group with any other party.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0
	(ii) Shared power to vote or to direct the vote: 5,010,846
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: 5,010,846
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Fennell Todd W.

Signature:	Diana L. Hayes
Name/Title:	Attorney-in-fact
Date:	08/14/2026