IRON MOUNTAIN INC

(Zip Code)

(617)535-4766

(Registrant’s Telephone Number, Including Area Code)

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Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

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Securities Registered Pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 5.02. Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

(e) The Annual Meeting of Stockholders of Iron Mountain Incorporated (the "Company") was held on May 29, 2025 (the "Annual Meeting"). At the Annual Meeting, the Company’s stockholders approved an amendment (the "Plan Amendment") to the Iron Mountain Incorporated 2014 Stock and Cash Incentive Plan (the "2014 Plan"), to increase the number of shares of the Company’s common stock authorized for issuance thereunder by 4,600,000 from 20,750,000 to 25,350,000, and to extend the termination date of the 2014 Plan from May 12, 2031 to May 29, 2035. The material terms of the 2014 Plan, as amended by the Plan Amendment, are summarized in the Company’s Proxy Statement for the Annual Meeting dated April 18, 2025, as supplemented on May 5, 2025 (the “Proxy Statement”). A copy of the Plan Amendment is filed as Exhibit 10.1 hereto and is incorporated herein by reference.

Item 5.07. Submission of Matters to a Vote of Security Holders.

At the Annual Meeting, the Company’s stockholders elected ten directors, each for a one-year term of office to serve until the Company’s 2026 Annual Meeting of Stockholders, or until their successors are elected and qualified. The nominated directors received the following votes:

At the Annual Meeting, the Company’s stockholders approved an amendment to the Iron Mountain Incorporated 2014 Stock and Cash Incentive Plan, which was previously approved by the Board of Directors. This proposal received the following votes: