Iron Mountain (IRM) DEFA14A Additional proxy soliciting materials

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of

the Securities Exchange Act of 1934 (Amendment No.)

Filed by the Registrant x
Filed by a Party other than the Registrant o
Check the appropriate box:
o	Preliminary Proxy Statement
o	Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))
o	Definitive Proxy Statement
x	Definitive Additional Materials
o	Soliciting Material under §240.14a-12

IRON MOUNTAIN INCORPORATED
(Name of Registrant as Specified In Its Charter)
(Name of Person(s) Filing Proxy Statement, if other than the Registrant)
Payment of Filing Fee (Check the appropriate box):
x	No fee required.
o	Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11.
	(1)	Title of each class of securities to which transaction applies:
	(2)	Aggregate number of securities to which transaction applies:
	(3)	Per unit price or other underlying value of transaction computed pursuant to Exchange Act Rule 0-11 (set forth the amount on which the filing fee is calculated and state how it was determined):
	(4)	Proposed maximum aggregate value of transaction:
	(5)	Total fee paid:
o	Fee paid previously with preliminary materials.
o	Check box if any part of the fee is offset as provided by Exchange Act Rule 0-11(a)(2) and identify the filing for which the offsetting fee was paid previously. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.
	(1)	Amount Previously Paid:
	(2)	Form, Schedule or Registration Statement No.:
	(3)	Filing Party:
	(4)	Date Filed:

You are receiving this communication because you hold shares in the company named above. This is not a ballot. You cannot use this notice to vote these shares. This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. You may view the proxy materials online at www.proxyvote.com or easily request a paper copy (see reverse side). We encourage you to access and review all of the important information contained in the proxy materials before voting. Meeting Information See the reverse side of this notice to obtain proxy materials and voting instructions. M90385-P64831-Z65263 IRON MOUNTAIN INCORPORATED *** Exercise Your Right to Vote *** Important Notice Regarding the Availability of Proxy Materials for the Stockholder Meeting to Be Held on May 28, 2015. IRON MOUNTAIN INCORPORATED INVESTOR RELATIONS ONE FEDERAL STREET BOSTON, MA 02110 Meeting Type: Annual Meeting For holders as of: April 2, 2015 Date: May 28, 2015 Time: 9:00 AM Local Time Location: Sullivan & Worcester LLP One Post Office Square 21st Floor Boston, MA 02109

Before You Vote How to Access the Proxy Materials Proxy Materials Available to VIEW or RECEIVE: How To Vote Please Choose One of the Following Voting Methods Vote In Person: Many stockholder meetings have attendance requirements including, but not limited to, the possession of an attendance ticket issued by the entity holding the meeting. Please check the meeting materials for any special requirements for meeting attendance. At the meeting, you will need to request a ballot to vote these shares. Directions to the meeting can be found at www.proxyvote.com. Vote By Internet: To vote now by Internet, go to www.proxyvote.com. Have the information that is printed in the box marked by the arrow (located on the following page) available and follow the instructions. Vote By Mail: You can vote by mail by requesting a paper copy of the materials, which will include a proxy card. Requests, instructions and other inquiries sent to this e-mail address will NOT be forwarded to your investment advisor. Please make the request as instructed above on or before May 14, 2015 to facilitate timely delivery. How to View Online: Have the information that is printed in the box marked by the arrow (located on the following page) and visit: www.proxyvote.com. How to Request and Receive a PAPER or E-MAIL Copy: If you want to receive a paper or e-mail copy of these documents, you must request one. There is NO charge for requesting a copy. Please choose one of the following methods to make your request: 1) BY INTERNET: www.proxyvote.com 2) BY TELEPHONE: 1-800-579-1639 3) BY E-MAIL*: sendmaterial@proxyvote.com * If requesting materials by e-mail, please send a blank e-mail with the information that is printed in the box marked by the arrow (located on the following page) in the subject line. 1. Notice and Proxy Statement 2. Annual Report Proxy Materials Available to VIEW or RECEIVE: M90386-P64831-Z65263 .XXXX XXXX XXXX XXXX .XXXX XXXX XXXX XXXX .XXXX XXXX XXXX XXXX

Voting Items M90387-P64831-Z65263 1b. Ted R. Antenucci 1a. Jennifer Allerton 1g. Per-Kristian Halvorsen 1e. Kent P. Dauten 1c. Pamela M. Arway 1d. Clarke H. Bailey 1f. Paul F. Deninger 1h. William L. Meaney 1i. Walter C. Rakowich 1j. Alfred J. Verrecchia 1. For the election of ten (10) directors to the Iron Mountain Incorporated Board of Directors for a one-year term or until their successors are elected and qualified. Nominees: The Board of Directors recommends you vote FOR the following: 2. The approval of a non-binding, advisory resolution approving the compensation of our named executive officers as described in the Iron Mountain Incorporated Proxy Statement. 3. The ratification of the selection by the Audit Committee of Deloitte & Touche LLP as Iron Mountain Incorporated's independent registered public accounting firm for the year ending December 31, 2015. NOTE: In their discretion, the proxies are authorized to vote upon such other business as may properly come before the Annual Meeting of Stockholders or any postponement or adjournment thereof. The Board of Directors recommends you vote FOR proposals 2 and 3.

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