irm-20260309

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 8-K

CURRENT REPORT PURSUANT
TO SECTION 13 OR 15(d) OF THE
SECURITIES EXCHANGE ACT OF 1934

Date of report (Date of earliest event reported): March 9, 2026

IRON MOUNTAIN INCORPORATED

(Exact Name of Registrant as Specified in Its Charter)

Delaware

(State or Other Jurisdiction of Incorporation)


1-13045						23-2588479
(Commission File Number)						(IRS Employer Identification No.)

85 New Hampshire Avenue, Suite 150, Portsmouth, New Hampshire

(Address of Principal Executive Offices)

03801

(Zip Code)

(617) 535-4766

(Registrant’s Telephone Number, Including Area Code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

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

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

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

Title of Each Class

Trading Symbol(s)

Name Of Each Exchange On Which Registered

Common Stock, $.01 par value per share

IRM

New York Stock Exchange

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 8.01. Other Events.

Iron Mountain Incorporated, or the Company, is filing as Exhibit 99.1 (which is incorporated by reference herein) a description of the material United States federal income tax considerations relating to the Company’s qualification and taxation as a real estate investment trust for United States federal income tax purposes and the acquisition, ownership and disposition of the Company’s stock. This description contained in Exhibit 99.1 replaces and supersedes prior descriptions of the federal income tax treatment of the Company and its stockholders to the extent they are inconsistent with the description contained in this Form 8-K and any reference to a prior description shall be deemed to be a reference to this description.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

8.1 Opinion of Sulli van & Worcester LLP as to tax matters (Filed herewith)

23.1 Consent of Sullivan & Worcester LLP (contained in Exhibit 8.1)

99.1 Material United States Federal Income Tax Considerations (Filed herewith)

104 The cover page from this Current Report on Form 8-K, formatted as Inline XBRL.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.


IRON MOUNTAIN INCORPORATED

By:			/s/ Michelle Altamura
Name:			Michelle Altamura
Title:			Executive Vice President, General Counsel and Secretary

Date: March 9, 2026

Iron Mountain Incorporated (Delaware) filed SEC Form 8-K: Other Events, Financial Statements and Exhibits