X0306 4 2014-11-04 0 0001020569 IRON MOUNTAIN INC IRM 0001183331 BAILEY CLARK H 10 OXFORD ROAD LARCHMONT NY 10538 1 0 0 0 Common Stock, par value $.01 per share 2014-11-04 4 A 0 10226 0 A 151595 D Common Stock, par value $.01 per share 2014-11-04 4 A 0 837 0 A 12409 I See footnote Common Stock, par value $.01 per share 2014-11-04 4 A 0 837 0 A 12409 I See footnote Phantom Stock 2014-11-04 4 A 0 1272.6247 0 A Common Stock 1272.6247 18703.3178 D This report reflects shares received by the Reporting Person as a result of the Reporting Person's receipt of his pro rata portion of a special distribution declared by the Board of Directors of the issuer on September 15, 2014 and paid on November 4, 2014 (the "Special Distribution"). Shares held by the Clarke H. Bailey GST Trust for the benefit of Trent S. Bailey. Shares held by the Clarke H. Bailey GST Trust for the benefit of Turner H. Bailey. Pursuant to the Reporting Person's election to participate in the Iron Mountain Incorporated Directors Deferred Compensation Plan, the shares of phantom stock (the "Phantom Shares") become payable in shares of Iron Mountain Incorporated common stock following the Reporting Person's disability or cessation of service as a director. Each Phantom Share is the economic equivalent of one share of common stock. These shares give effect to dividends paid on common stock as if reinvested in phantom stock. Includes 355 previously unreported unvested Phantom Shares allocated on November 4, 2014 in connection with the Special Distribution and with respect to certain restricted stock units ("RSUs") granted on May 29, 2014, which RSUs shall vest on the one year anniversary of the grant date (or, if earlier, the annual meeting of stockholders that is closest to the one year anniversary). /s/ Sarah Cammarata, under Power of Attorney dated September 16, 2010, from Clarke H. Bailey 2014-11-06