# EDGAR Filing Document

**Accession Number:** 0001020569
**File Stem:** 0001308179-23-000453
**Filing Date:** 2023-3
**Character Count:** 7405
**Document Hash:** db367d52006820f3a1d6d8d1e72c1db1
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001308179-23-000453.hdr.sgml**: 20230330

**ACCESSION NUMBER**: 0001308179-23-000453

**CONFORMED SUBMISSION TYPE**: DEFA14A

**PUBLIC DOCUMENT COUNT**: 9

**FILED AS OF DATE**: 20230330

**DATE AS OF CHANGE**: 20230330

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** IRON MOUNTAIN INC
- **CENTRAL INDEX KEY:** 0001020569
- **STANDARD INDUSTRIAL CLASSIFICATION:** REAL ESTATE INVESTMENT TRUSTS [6798]
- **IRS NUMBER:** 232588479
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** DEFA14A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-13045
- **FILM NUMBER:** 23780914

**BUSINESS ADDRESS:**
- **STREET 1:** 85 NEW HAMPSHIRE AVENUE, SUITE 150
- **STREET 2:** PEASE INTERNATIONAL TRADEPORT
- **CITY:** PORTSMOUTH
- **STATE:** NH
- **ZIP:** 03801
- **BUSINESS PHONE:** 617-535-4781

**MAIL ADDRESS:**
- **STREET 1:** ONE FEDERAL STREET
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02110

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** IRON MOUNTAIN INC/PA
- **DATE OF NAME CHANGE:** 20000201

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** PIERCE LEAHY CORP
- **DATE OF NAME CHANGE:** 19960807

UNITED STATES<br>SECURITIES AND EXCHANGE COMMISSION<br>Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the <br>Securities Exchange Act of 1934 (Amendment No.)

☑ Filed by the Registrant ☐ Filed by a party other than the Registrant

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| | |
|:---|:---|
| CHECK THE APPROPRIATE BOX: | CHECK THE APPROPRIATE BOX: |
| ☐ | Preliminary Proxy Statement |
| ☐ | Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) |
| ☐ | Definitive Proxy Statement |
| ☑ | Definitive Additional Materials |
| ☐ | Soliciting Material under §240.14a-12 |

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![](irm4112791-defa14alogo.jpg)

**IRON MOUNTAIN INCORPORATED**

(Name of Registrant as Specified In Its Charter)<br>(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

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| | |
|:---|:---|
| PAYMENT OF FILING FEE (CHECK ALL BOXES THAT APPLY): | PAYMENT OF FILING FEE (CHECK ALL BOXES THAT APPLY): |
| ☑ | No fee required |
| ☐ | Fee paid previously with preliminary materials |
| ☐ | Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11 |

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![](irm4112791-defa14ax1x1.jpg)

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| | |
|:---|:---|
|  | Your **Vote** Counts! |
|  | **IRON MOUNTAIN INCORPORATED** |
|  | 2023 Annual Meeting |
|  | Vote by May 8, 2023 |
|  | 11:59 PM ET |
| &nbsp;&nbsp;&nbsp;IRON MOUNTAIN INCORPORATED<br> INVESTOR RELATIONS<br> 85 NEW HAMPSHIRE AVE, SUITE 150<br> PORTSMOUTH, NH 03801 |  |
| V09061-P83659 |  |

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You invested in IRON MOUNTAIN INCORPORATED and it's time to vote!

You have the right to vote on proposals being presented at the Annual Meeting. **This is an important notice regarding the availability of proxy material for the stockholder meeting to be held on May 9, 2023.**

Get informed before you vote

View the Notice and Proxy Statement and Annual Report online OR you can receive a free paper or email copy of the material(s) by requesting prior to April 25, 2023. If you would like to request a copy of the material(s) for this and/or future stockholder meetings, you may (1) visit www.ProxyVote.com, (2) call 1-800-579-1639 or (3) send an email to sendmaterial@proxyvote.com. If sending an email, please include your control number (indicated below) in the subject line. Unless requested, you will not otherwise receive a paper or email copy.

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|:---|:---|:---|
| ![](irm4112791-defa14ax1x2.jpg) | &nbsp;&nbsp;&nbsp;For complete information and to vote, visit **www.ProxyVote.com** | &nbsp;&nbsp;&nbsp;For complete information and to vote, visit **www.ProxyVote.com** |
| ![](irm4112791-defa14ax1x2.jpg) | Control # | ![](irm4112791-defa14ax1x4.jpg) |

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|:---|:---|
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ![](irm4112791-defa14ax1x3.jpg)<br> **Smartphone users**<br>Point your camera here and<br> vote without entering a<br> control number<br>| ![](irm4112791-defa14ax1x5.jpg)<br> **Vote Virtually at the Meeting\***<br>May 9, 2023<br> 12:00 PM EDT<br>Virtually at:<br>www.virtualshareholdermeeting.com/IRM2023 |

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\* Please check the meeting materials for any special requirements for meeting attendance. <br>

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**Vote at www.ProxyVote.com**

 **THIS IS NOT A VOTABLE BALLOT**<br>This is an overview of the proposals being presented at the upcoming stockholder meeting. Please follow the instructions on the reverse side to vote these important matters.<br>

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| | | |
|:---|:---|:---|
| **Voting Items** | **Voting Items** | **Board<br>Recommends** |
| 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.<br> **Nominees:** |  |
| 1a. | Jennifer Allerton | ![](irm4112791-defa14ax1x6.jpg) **For** |
| 1b. | Pamela M. Arway | ![](irm4112791-defa14ax1x6.jpg) **For** |
| 1c. | Clarke H. Bailey | ![](irm4112791-defa14ax1x6.jpg) **For** |
| 1d. | Kent P. Dauten | ![](irm4112791-defa14ax1x6.jpg) **For** |
| 1e. | Monte Ford | ![](irm4112791-defa14ax1x6.jpg) **For** |
| 1f. | Robin L. Matlock | ![](irm4112791-defa14ax1x6.jpg) **For** |
| 1g. | William L. Meaney | ![](irm4112791-defa14ax1x6.jpg) **For** |
| 1h. | Wendy J. Murdock | ![](irm4112791-defa14ax1x6.jpg) **For** |
| 1i. | Walter C. Rakowich | ![](irm4112791-defa14ax1x6.jpg) **For** |
| 1j. | Doyle R. Simons | ![](irm4112791-defa14ax1x6.jpg) **For** |
| 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. | ![](irm4112791-defa14ax1x6.jpg) **For** |
| 3. | The approval on a non-binding, advisory basis of the frequency (every one, two or three years) of future non-binding, advisory votes of stockholders on the compensation of our named executive officers. | ![](irm4112791-defa14ax1x7.jpg) **Year** |
| 4. | 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, 2023. | ![](irm4112791-defa14ax1x6.jpg) **For** |
| **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. | **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. | **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. |
| **Prefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click "Delivery Settings".** | **Prefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click "Delivery Settings".** | **Prefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click "Delivery Settings".** |
| V09062-P83659 | V09062-P83659 | V09062-P83659 |

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