Company: PRTA
Filing Date: 2025-09-25
Form Type: PRE 14A
Source: 0001140361-25-036135
Chunk: 6

Company: PROTHENA CORP PUBLIC LTD CO
Filing Date: 2025-09-25
Form: PRE 14A
Chunk 6
---
 voting instructions with these proxy

materials from that organization rather than from us. Simply complete and mail the voting instruction card to ensure that your vote is counted, or follow such instructions to submit your vote by the internet or telephone, if the instructions provide for internet and telephone voting. To vote in person at the EGM, you must obtain a valid proxy from your broker, bank, or other agent. Follow the instructions from your broker, bank, or other agent included with these proxy materials, or contact your broker, bank, or other agent to request a proxy form.

| 4. |     | Who counts the votes? |

Broadridge Financial Solutions, Inc. (“Broadridge”) has been engaged as our independent agent to tabulate shareholder votes.

| 5. |     | How are votes counted? |

For Proposal No.1, an affirmative vote of 75 percent of the votes cast in person or by proxy at the EGM is required for approval. If your shares are held by a broker on your behalf (that is, in “street name”), please instruct your broker on how to vote your shares. If you do not provide voting instructions, your shares will not be voted on any proposal that is considered to be “non-routine” under NYSE rules, in which case the broker does not have discretionary authority to vote. This is called a “broker non-vote.” We have been advised by the NYSE that Proposal No. 1 is considered to be a “routine” matter, meaning that if you do not return voting instructions to your broker by its deadline, your shares may be voted by your broker in its discretion. As a result, we do not expect any broker non-votes on Proposal No. 1. Nevertheless, we strongly encourage you to provide voting instructions to your broker to ensure that your vote is counted on the proposal. If shareholders abstain from voting, including brokers holding their clients’ shares of record who cause abstentions to be recorded, these shares will be considered present and entitled to vote at the EGM and will be counted towards determining whether or not a quorum is present. Abstentions will not, however, be considered votes cast at the EGM. Because the approval of Proposal No.1 is based on the votes cast at the EGM, abstentions will not have any effect on the outcome of voting of the proposal.

| 6. |     | How many votes do I have? |

On each matter to be voted upon, you have one vote for each ordinary