X0508 4 2024-02-15 0 0001333274 MERCER INTERNATIONAL INC. MERC 0001927186 BUENO ESTRADA JUAN CARLOS SUITE 1120 700 WEST PENDER STREET VANCOUVER A1 V6C 1G8 BRITISH COLUMBIA, CANADA 1 1 0 0 CEO & President 0 Common Stock 2024-02-15 4 M 0 58754 0 A 86254 D Common Stock 2024-02-15 4 F 0 26439 7.785 D 59815 D Performance Share Units 0 2024-02-15 4 A 0 58754 0 A Common Stock 58754 58754 D Performance Share Units 0 2024-02-15 4 M 0 58754 0 D Common Stock 58754 0 D Represents the conversion of performance share units ("PSUs"). Represents the average of the intraday high and low trading price on February 15, 2024. Represents the vesting on February 15, 2024 of PSUs awarded to the reporting person based on the achievement of certain specified performance criteria, including company performance and share price performance during the 2021 to 2023 performance period. /S/ Juan Carlos Bueno Estrada 2023-02-16