[SCHEDULE 13G/A] Prothena Corporation plc SEC Filing

Rhea-AI Filing Summary

Todd W. Fennell filed an amendment to a Schedule 13G disclosing beneficial ownership of 4,350,846 ordinary shares of Prothena Corporation plc, representing approximately 8.08% of the 53,826,982 shares outstanding. The reported holdings consist of 40,000 shares held by an irrevocable gift trust and 4,310,846 shares held by multiple grantor retained annuity trusts, for which Mr. Fennell serves as independent trustee.

The filing shows shared voting and shared dispositive power over all reported shares and includes a certification that the securities are not held to change or influence control of the issuer. This disclosure provides investors a clear view of a materially significant, statedly passive stake in PRTA and identifies the legal vehicles through which the interest is held.

Positive

• Material disclosure of a significant 8.08% stake (4,350,846 shares) in Prothena enhances market transparency
• Clear identification of ownership vehicles: 40,000 shares in an irrevocable gift trust and 4,310,846 shares in grantor retained annuity trusts
• Filing includes an explicit certification that the shares are not held to change or influence control, indicating a stated passive intent

Negative

• None.

Insights

Financial Analyst

Passive 8.08% stake disclosed; material in size but filed as non-control, so immediate market impact is likely limited.

The filing reports 4,350,846 shares (≈8.08% of 53,826,982 outstanding). From a capital-markets perspective, stakes above 5% attract attention because they can influence liquidity and perceptions of insider alignment, but this Schedule 13G/A includes a certification that the holdings are not intended to influence control, indicating a passive position. The shares are held through trusts with shared voting/dispositive powers, which can affect how quickly the position could be mobilized if intentions changed.

Corporate Governance Expert

Disclosure enhances governance transparency; shared trustee roles warrant monitoring but filing signals no control attempt.

The report itemizes ownership through an irrevocable gift trust (40,000 shares) and multiple grantor retained annuity trusts (4,310,846 shares) with the reporting person acting as independent trustee. That structure gives shared voting and dispositive power, which is important for understanding who can exercise influence in practice. The explicit certification that the position is not held to affect control reduces immediate governance concerns, though investors should note the legal vehicles and power allocations disclosed.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 4)

PROTHENA CORP PUBLIC LTD CO

(Name of Issuer)

Ordinary Shares, $0.01 par value

(Title of Class of Securities)

G72800108

(CUSIP Number)

06/30/2025

(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)

SCHEDULE 13G

CUSIP No. 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 4,350,846.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 4,350,846.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

4,350,846.00

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)

8.1 %

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, 77 SIR JOHN ROGERSON'S QUAY, BLOCK C, 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 4,350,846 Ordinary Shares. This amount consists of (i) 40,000 owned by an irrevocable gift trust, for which the Reporting Person serves as an independent trustee, and (ii) 4,310,846 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, 2025, the number of shares outstanding as of July 25, 2025 was 53,826,982. The Ordinary Shares which the Reporting Person may be deemed to beneficially own constitute approximately 8.08 percent of such total number of shares.
(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: 4,350,846
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: 4,350,846
Item 5.	Ownership of 5 Percent or Less of a Class.
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:	/s/ Diana L. Hayes
Name/Title:	attorney-in-fact
Date:	08/13/2025

Comments accompanying signature: Pursuant to a limited power of attorney dated as of February 8, 2024, a copy of which is on file with the Commission.

FAQ

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

The filing reports 4,350,846 ordinary shares beneficially owned by Todd W. Fennell, representing approximately 8.08% of outstanding shares.

Through what vehicles are Fennell's PRTA shares held?

The shares are held via an irrevocable gift trust (40,000 shares) and multiple grantor retained annuity trusts (4,310,846 shares); Mr. Fennell serves as independent trustee.

Does Todd W. Fennell have sole voting or dispositive power over these shares?

No. The filing states 0 sole voting power and 0 sole dispositive power, and reports 4,350,846 shares of shared voting and shared dispositive power.

Is the disclosed position intended to influence control of Prothena (PRTA)?

The certification in the filing states the securities were not acquired and are not held to change or influence control of the issuer.

What form was filed and what event date is associated with the filing?

A Schedule 13G/A (Amendment No. 4) was filed in relation to the event date 06/30/2025.