IRON MOUNTAIN INC

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM 10-K

Commission File Number 1-13045

(Exact name of Registrant as Specified in Its Charter)

Delaware

(State or other jurisdiction of incorporation)

85 New Hampshire Avenue, Suite 150

Portsmouth, New Hampshire

(Address of principal executive offices)

23-2588479

(I.R.S. Employer Identification No.)

(Zip Code)

617-535-4766

(Registrant’s telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☒ No ☐

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ☐No ☒

Indicate by check mark whether the registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically, every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer”, “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act. (Check one):

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. Yes☒ No ☐

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements.☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to § 240.10D-1(b). ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No☒

As of June 30, 2023, the aggregate market value of the Common Stock of the registrant held by non-affiliates of the registrant was approximately $16.1 billion based on the closing price on the New York Stock Exchange on such date.

Number of shares of the registrant’s Common Stock at February 16, 2024:292,275,668

DOCUMENTS INCORPORATED BY REFERENCE

Certain information required in Items 10, 11, 12, 13 and 14 of Part III of this Annual Report on Form 10-K (the “Annual Report”) is incorporated by reference from our definitive Proxy Statement for our 2024 Annual Meeting of Stockholders (our “Proxy Statement”) to be filed with the Securities and Exchange Commission (the “SEC”) within 120 days after the close of the fiscal year ended December 31, 2023.