Registered in Ireland - No. 518146
77 Sir John Rogerson’s Quay, Block C, Grand Canal
Docklands, Dublin 2, D02 VK60, Ireland
NOTICE OF EXTRAORDINARY GENERAL MEETING OF SHAREHOLDERS TO BE HELD ON NOVEMBER 19, 2025
To the Shareholders of Prothena Corporation plc:
NOTICE IS HEREBY GIVEN that an Extraordinary General Meeting of Shareholders (the “EGM”) of Prothena Corporation plc, an Irish public limited company (the “Company”), will be held on Wednesday, November 19, 2025, at 4:00 p.m. local time, at the offices of the Company’s legal counsel, A&L Goodbody LLP, 25 North Wall Quay, Dublin 1, D01 H104, Ireland, for the following purposes:
1.
| To approve the reduction of Company capital to facilitate the creation of distributable reserves; and |
2.
| To transact such other business as may properly come before the EGM or any adjournment or postponement thereof. |
The text of Proposal No.1 is set out in the Proxy Statement accompanying this Notice. Pursuant to our Constitution and Irish law, Proposal No. 1 is being proposes as a special resolution requiring the approval of at least 75% of the votes cast at the EGM.
Only shareholders who owned our ordinary shares at the close of business on September 24, 2025, may vote at the EGM. Each shareholder of record will be entitled to one vote per ordinary share on each matter submitted to a vote of the shareholders, as long as those shares are represented at the EGM, either in person or by proxy. Shareholders who are entitled to attend and vote at the EGM are entitled to appoint a proxy or proxies to attend and vote on their behalf at the EGM; such proxy is not required to be a shareholder of the Company.
Our Board of Directors unanimously recommends that you vote FOR the approval of the reduction of the Company’s capital to facilitate the creation of distributable reserves, as described in Proposal No. 1.
For the EGM, we have elected to use the internet as the primary means of providing our proxy materials to shareholders. Consequently, some shareholders may not receive paper copies of our proxy materials. We intend to send shareholders a Notice of Internet Availability of Proxy Materials with instructions for accessing the proxy materials and for voting via the internet. The Notice of Internet Availability of Proxy Materials will also provide the date, time, and location of the EGM; the matters to be acted upon at the meeting and the Board of Directors’ recommendation with regard to each matter; a toll-free number, an e-mail address, and a website where shareholders can request a paper or e-mail copy of our Proxy Statement and form of proxy card; information on how to access their proxy card; and information on how to attend the meeting and vote in person.
You are cordially invited to attend the EGM, but whether or not you expect to attend in person, you are urged to complete, sign, and date your proxy card and return it by mail or follow the alternative voting procedures described in the Notice of Internet Availability of Proxy Materials or the proxy card.
| | | | | |
| | | | By Order of the Board of Directors | |
| | | |
| |
| | | | Michael J. Malecek
Chief Legal Officer & Company Secretary
Dublin, Ireland
[ ], 2025 | |
| | | | | |
