X0202 SCHEDULE 13G/A 0001045463 XXXXXXXX LIVE 6 Ordinary Shares, $0.01 par value 05/07/2026 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) SCULLY WILLIAM P FL 793000.00 4585846.00 793000.00 4585846.00 5378846.00 10.3 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. William P Scully 771 Manatee Cove, Vero Beach, Florida 32963 Florida Y The Reporting Person may be deemed to be the beneficial owner of 5,378,846 Ordinary Shares. This amount consists of (i) 80,000 Ordinary Shares owned by Manatee Equity Fund LLC, of which the Reporting Person is the sole manager with sole voting and dispositive power, (ii) 713,000 Ordinary Shares owned by the Reporting Persons IRA, over which he has sole voting and dispositive power, (iii) 42,000 Ordinary Shares owned by the Reporting Persons spouses IRA, over which he may be deemed to have shared voting and dispositive power, (iv) 10,000 Ordinary Shares owned by the Reporting Persons spouse, over which he may be deemed to have shared voting and dispositive power (v) 23,000 Ordinary Shares owned by an IRA subject to an investment management agreement over which the Reporting Person may be deemed to have shared voting and dispositive power by reason of his right to terminate such agreement, (vii) 4,470,846 Ordinary Shares owned in the aggregate by various grantor retained annuity trusts, which have an independent trustee, but over which the Reporting Person may be deemed to have shared voting and dispositive power by reason of his retained right to substitute assets in such trusts, and (viii) 40,000 Ordinary Shares owned by another trust, which has an independent trustee, but over which the Reporting Person may be deemed to have shared voting and dispositive power by reason of his retained right to substitute assets in such trust According to the Issuers most recent Quarterly Report on Form 10-Q for the quarter ended March 31, 2026, as filed with the Securities and Exchange Commission on May 7, 2026, the number of shares outstanding as of April 30, 2026 was 52,353,237. The Ordinary Shares which the Reporting Person may be deemed to beneficially own constitute approximately 10.27% of such total number of shares 793,000 4,585,846 793,000 4,585,846 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. SCULLY WILLIAM P /s/ Diana L. Hayes 05/11/2026