Iron Mountain Inc.

Item 1.01. Entry into a Material Definitive Agreement. Issuance of 6.250% Senior Notes due 2035 On June 26, 2026, Iron Mountain Incorporated (the “Company”) completed a private offering of $1,500,000,000 in aggregate principal amount of 6.250% Senior Notes due 2035 (the “Notes”), sold at 100.00% of par. The net proceeds from the offering were approximately $1,481.8 million, after deducting discounts to the initial purchasers and estimated offering expenses. The Company intends to use the net proceeds from the offering of the Notes to repay all or a portion of the outstanding borrowings under the Company’s revolving credit facility and to pay related fees and expenses, with any remaining proceeds to be used for general corporate purposes. The Notes were offered and sold only to persons reasonably believed to be qualified institutional buyers pursuant to Rule 144A under the Securities Act of 1933, as amended (the “Securities Act”), and to non-United States persons in compliance with Regulation S under the Securities Act. The Notes have not been registered under the Securities Act or under any state securities law, and may not be offered or sold in the United States absent registration or an applicable exemption from, or in a transaction not subject to, the registration requirements of the Securities Act and applicable state securities laws. The Notes were issued under an indenture, dated as of June 26, 2026 (the “Indenture”), by and among the Company, the Subsidiary Guarantors (as defined below) and Computershare Trust Company N.A., as trustee. The Company will pay 6.250% interest per annum on the principal amount of the Notes, payable semi-annually on January 15 and July 15 of each year. Interest on the Notes will accrue from June 26, 2026, and the first interest payment date for the Notes will be January 15, 2027. The Notes will mature on January 15, 2035, unless they are earlier redeemed or repurchased in accordance with the terms set forth in the Indenture. The Notes are initially jointly and severally guaranteed on an unsecured senior basis by the Company’s direct and indirect United States subsidiaries that represent the substantial majority of its United States operations (the “Subsidiary Guarantors”). The Notes and the guarantees will be the Company’s and the Subsidiary Guarantors’ general unsecured senior obligations, will be pari passu in right of payment with all of the Company’s and the Subsidiary Guarantors’ existing and future senior debt and will rank senior in right of payment to all of the Company’s and the Subsidiary Guarantors’ existing and future subordinated debt. The Notes and the guarantees are effectively subordinated to the Company’s and the Subsidiary Guarantors’ secured indebtedness, to the extent of the value of the collateral securing such indebtedness, and structurally subordinated to all liabilities of the Company’s subsidiaries that do not guarantee the Notes. Prior to July 15, 2029, the Company may, at its option, redeem all or a portion of the Notes at the applicable make-whole price set forth in the Indenture. Prior to July 15, 2029, the Company may, at its option, redeem up to 40% in aggregate principal amount of the Notes with an amount not greater than the net proceeds of certain equity offerings at the redemption price set forth in the Indenture so long as at least 50% of the aggregate principal amount of the Notes (originally issued) remains outstanding immediately afterwards. The Company has the option to redeem all or a portion of the Notes at any time on or after July 15, 2029 at the redemption prices set forth in the Indenture. Upon certain changes of control, the Company may be required to offer to repurchase the Notes under the terms set forth in the Indenture. The Indenture provides for customary “events of default” which could cause, or permit, the acceleration of the Notes. The Indenture contains certain restrictive covenants, including covenants that restrict the Company’s ability to enter into sale leaseback transactions, create or permit liens and take certain other corporate actions. This brief description of the Notes is qualified in its entirety by reference to the Indenture, attached hereto as Exhibit 4.1, which is incorporated herein by reference. This Current Report on Form 8-K shall not constitute an offer to sell or the solicitation of an offer to buy securities, nor shall there be any sale of these securities in any state or other jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.

Item 2.03. Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The information included in Item 1.01 of this Current Report on 8-K is incorporated into this Item 2.03 by reference.