X0306 4 2016-02-18 0 0001020569 IRON MOUNTAIN INC IRM 0001590872 Tsolakis Anastasios C/O IRON MOUNTAIN INCORPORATED ONE FEDERAL STREET BOSTON MA 02110 0 1 0 0 EVP, CIO, Global Svcs. Officer Common Stock, par value $.01 per share 2016-02-19 4 M 0 1543 0 A 58986 D Common Stock, par value $.01 per share 2016-02-19 4 F 0 486 28.95 D 58500 D Employee Stock Option (Right to Buy) 29.27 2016-02-18 4 A 0 39441 0 A 2026-02-18 Common Stock 39441 39441 D Restricted Stock Units 2016-02-18 4 A 0 6149 0 A Common Stock 6149 6149 D Restricted Stock Units 2016-02-19 4 M 0 1543 0 D Common Stock 1543 3092 D This acquisition is reported to reflect the partial vesting of restricted stock units ("RSUs") previously granted to the Reporting Person on February 19, 2015. This stock option becomes exercisable in three substantially equal annual installments beginning on the first anniversary of the date of grant. Each RSU represents a contingent right to receive one share of Iron Mountain Incorporated common stock ("Common Stock"). The RSUs vest in three substantially equal annual installments beginning on the first anniversary of the grant date. The RSUs, representing a contingent right to receive a total of 4,635 shares of Common Stock, were granted to the Reporting Person on February 19, 2015 and vest in three substantially equal annual installments beginning on the first anniversary of the grant date. /s/ Garry B. Watzke, under Power of Attorney dated November 1, 2013, from Anastasios Tsolakis 2016-02-22