X0202 SCHEDULE 13G/A 0002011420 XXXXXXXX LIVE 7 Ordinary Shares, $0.01 par value 08/18/2026 0001559053 PROTHENA CORP PUBLIC LTD CO G72800108 77 SIR JOHN ROGERSON'S QUAY, BLOCK C GRAND CANAL DOCKLANDS DUBLIN 2 L2 D02 VK60 Rule 13d-1(c) Fennell Todd W. FL 0.00 5248846.00 0.00 5248846.00 5248846.00 10.2 IN See Item 4 PROTHENA CORP PUBLIC LTD CO 77 SIR JOHN ROGERSON'S QUAY, BLOCK C, GRAND CANAL DOCKLANDS, DUBLIN 2, IRELAND, D02 VK60. Todd W. Fennell 979 Beachland Boulevard, Vero Beach, Florida 32963 Florida Y The Reporting Person may be deemed to be the beneficial owner of 5,248,846 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) 5,033,846 Ordinary Shares owned in the aggregate by various grantor retained annuity trusts, for which the Reporting Person serves as an independent trustee. 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 10.22% 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. 0 5,248,846 0 5,248,846 Y Y Y Y Y N 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. Fennell Todd W. /s/ Diana L. Hayes 08/19/2026 *Pursuant to a Limited Power of Attorney dated as of September 9, 2025, a copy of which is on file with the Commission.