X0306 4 2019-02-14 0 0001333274 MERCER INTERNATIONAL INC. MERC 0001732127 Koppensteiner Adolf SUITE 1120 700 WEST PENDER STREET VANCOUVER A1 V6C 1G8 BRITISH COLUMBIA, CANADA 0 1 0 0 Chief Operating Officer Common Stock 2019-02-14 4 M 0 30078 0 A 34754 D Common Stock 2019-02-14 4 F 0 15039 15.03 D 19715 D Performance Share Units 0 2019-02-14 4 A 0 30078 0 A Common Stock 30078 30078 D Performance Share Units 0 2019-02-14 4 M 0 30078 0 D Common Stock 30078 0 D Represents the conversion of vested performance share units ("PSUs"). Represents the average of the intraday high and low trading price on February 14, 2019. Represents the vesting on February 13, 2019 of PSUs awarded to the reporting person based on the achievement of certain specified performance criteria, including company performance, share price performance and individual performance during the 2016 to 2018 performance period. /s/ Adolf Koppensteiner 2019-02-14