X0306 4 2016-02-16 0 0001020569 IRON MOUNTAIN INC IRM 0001291613 Cloutier Ernest W C/O IRON MOUNTAIN INCORPORATED ONE FEDERAL STREET BOSTON MA 02110 0 1 0 0 EVP, Gen. Counsel, Secretary Common Stock, par value $.01 per share 2016-02-16 4 M 0 2372 0 A 29853 D Common Stock, par value $.01 per share 2016-02-16 4 F 0 895 28.07 D 28958 D Restricted Stock Units 2016-02-16 4 M 0 2372 0 D Common Stock 2372 2380 D This acquisition is reported to reflect the partial vesting of restricted stock units ("RSUs") previously granted to the Reporting Person on February 13, 2014. 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 7,124 shares of Common Stock, were granted to the Reporting Person on February 13, 2014 and vest in three substantially equal annual installments beginning on the first anniversary of the grant date. The number of RSUs granted includes previously reported RSUs allocated on November 4, 2014 in connection with the special distribution declared by the Board of Directors of Iron Mountain Incorporated on September 15, 2014 and paid on November 4, 2014. /s/ Ernest W. Cloutier 2016-02-18