Company: PRTA
Filing Date: 2025-03-28
Form Type: DEF 14A
Source: 0001559053-25-000017
Chunk: 100

Company: PROTHENA CORP PUBLIC LTD CO
Filing Date: 2025-03-28
Form: DEF 14A
Chunk 100
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 issued under our equity compensation plans.

|                                 |     | -a                                                                                          |            |            |     | -b                                                                             |        |     | -c                                                                                                                                             |           |           |
| Plan Category                   |     | Number of securities to be issued upon exercise of outstanding options, warrants and rights |            |            |     | Weighted-average exercise price of outstanding options, warrants and rights(1) |        |     | Number of securities remaining available for future issuance under equity compensation plans (excluding securities reflected in column (a))(2) |           |           |
| Equity Compensation Plans       
 Approved by Shareholders(3)     |     |                                                                                             | 10,410,127 |            |     |                                                                                | $28.40 |     |                                                                                                                                                | 3,877,217 |           |
| Equity Compensation Plans       
 Not Approved by Shareholders(4) |     |                                                                                             |    703,246 |            |     |                                                                                | $33.06 |     |                                                                                                                                                |   341,584 |           |
| Total                           |     |                                                                                             |            | 11,113,373 |     |                                                                                | $28.70 |     |                                                                                                                                                |           | 4,218,801 |

(1) The weighted-average exercise price does not consider awards that have no exercise price, such as restricted share units.

(2) Represents ordinary shares available for issuance under our 2018 LTIP and our 2020 EIIP that may be granted in the form of stock options, stock appreciation rights, restricted shares, restricted share units, performance share units and other share-based awards. This number of shares will be reduced by 1.5 shares for each share that may be issued under an award other than an option or stock appreciation right.

(3) Column (a) represents the sum of nonqualified stock options and restricted share units outstanding under our 2012 LTIP and our 2018 LTIP, and column (c) represents ordinary shares available for future issuance under our 2018 LTIP.

(4) Column (a) represents nonqualified stock options outstanding under our 2020 EIIP, and column (c) represents ordinary shares available for future issuance under our 2020 EIIP.

| 2025 PROXY STATEMENT |     | 61 |

#### TABLE OF CONTENTS

### TRANSACTIONS WITH RELATED PERSONS AND INDEMNIFICATION
| Policies and Procedures on Transactions with Related Persons |

The Company has adopted