X0306 4 2019-02-19 0 0001020569 IRON MOUNTAIN INC IRM 0001346840 Keddy Patrick J C/O IRON MOUNTAIN INCORPORATED ONE FEDERAL STREET BOSTON MA 02110 0 1 0 0 EVP & GM, N. America W. Europe Common Stock, par value $.01 per share 2019-02-19 4 M 0 2568 0 A 23899 D Common Stock, par value $.01 per share 2019-02-19 4 F 0 1206 35.39 D 22693 D Common Stock, par value $.01 per share 2019-02-19 4 M 0 2160 0 A 24853 D Common Stock, par value $.01 per share 2019-02-19 4 F 0 1015 35.39 D 23838 D Common Stock, par value $.01 per share 2019-02-19 4 M 0 11841 0 A 35679 D Common Stock, par value $.01 per share 2019-02-19 4 F 0 5565 35.39 D 30114 D Restricted Stock Units 2019-02-19 4 M 0 2568 0 D Common Stock 2568 0 D Restricted Stock Units 2019-02-19 4 M 0 2160 0 D Common Stock 2160 2167 D Performance Units 2019-02-19 4 M 0 11841 0 D Common Stock 11841 0 D This acquisition is reported to reflect the partial vesting of restricted stock units ("RSUs") previously granted to the Reporting Person on February 18, 2016. This acquisition is reported to reflect the partial vesting of RSUs previously granted to the Reporting Person on February 16, 2017. This acquisition is reported to reflect the full vesting of performance units ("PUs") previously granted to the Reporting Person on February 18, 2016. Effective February 14, 2019, the Compensation Committee of Iron Mountain Incorporated's Board of Directors (the "Compensation Committee") determined the actual award of PUs under the grant after completion of the relevant performance period, and the PUs vested in full on February 18, 2019. Each RSU represents a contingent right to receive one share of Iron Mountain Incorporated common stock ("Common Stock"). The RSUs, representing a contingent right to receive a total of 7,687 shares of Common Stock, were granted to the Reporting Person on February 18, 2016 and have vested in full. The RSUs, representing a contingent right to receive a total of 6,486 shares of Common Stock, were granted to the Reporting Person on February 16, 2017 and vest in three substantially equal annual installments beginning on the first anniversary of the grant date. Each PU represents a contingent right to receive one share of Common Stock. The PUs were initially granted to the Reporting Person on February 18, 2016. Effective February 14, 2019, the Compensation Committee determined the actual award of PUs under the grant after completion of the relevant performance period, and the PUs vested in full on February 18, 2019. /s/ Elizabeth Tammaro, under Power of Attorney dated May 26, 2016, from Patrick Keddy 2019-02-21