UNITED STATES ~~STATESSECURITIES~~ 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): ~~May~~June 726, 2026

IRON MOUNTAIN INCORPORATED

(Exact Name of Registrant as Specified in Its Charter)

Delaware

(State or Other Jurisdiction of Incorporation)

1-13045	23-2588479	~~23-2588479~~
(Commission File Number)	(IRS Employer Identification No.)	~~(IRS Employer Identification No.)~~
85 New Hampshire Avenue, Suite 150 Portsmouth, New Hampshire	03801
(Address of Principal Executive Offices)	(Zip Code)

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 51.0701. ~~Submission~~ ofEntry ~~Matters~~into to a ~~Vote~~Material ofDefinitive ~~Security Holders~~Agreement.

Issuance ~~The Annual Meeting~~ of ~~Stockholders of Iron Mountain Incorporated (the "Company") was held on May 7, 2026 (the "Annual Meeting")~~6.250% AtSenior ~~the~~Notes ~~Annual~~due Meeting, the Company’s stockholders elected eleven directors, each for a one-year term of office to serve until the Company’s 2027 Annual Meeting of Stockholders, or until their successors are elected and qualified. The nominated directors received the following votes:2035

Name	For	Against	Abstain	Broker Non-Vote
Jennifer Allerton	228,147,317	3,714,104	258,469	29,485,212
Pamela M. Arway	224,276,516	7,584,348	259,026	29,485,212
Kent P. Dauten	222,084,314	9,771,888	263,688	29,485,212
June Yee Felix	231,457,579	403,644	258,667	29,485,212
Monte Ford	229,673,232	2,176,206	270,452	29,485,212
Christie Kelly	230,740,183	1,119,691	260,016	29,485,212
Robin L. Matlock	228,348,027	3,510,121	261,742	29,485,212
William L. Meaney	230,355,967	1,518,355	245,568	29,485,212
Walter C. Rakowich	221,243,149	10,628,182	248,559	29,485,212
Theodore R. Samuels	223,196,685	8,663,281	259,924	29,485,212
Doyle R. Simons	230,922,536	935,130	262,224	29,485,212

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.

AtThe Notes were offered and sold only to persons reasonably believed to be qualified institutional buyers pursuant to Rule 144A under the ~~Annual~~Securities ~~Meeting~~Act of 1933, as amended (the ~~Company’s~~“Securities ~~stockholders~~Act”), ~~approved~~and ato non-~~binding~~United ~~advisory~~States ~~resolution~~persons onin compliance with Regulation S under the ~~compensation~~Securities ~~paid~~Act. The toNotes have not been registered under the ~~Company’s~~Securities ~~named~~Act ~~executive~~or ~~officers~~under asany ~~disclosed~~state ~~pursuant~~securities tolaw, ~~Item~~and ~~402~~may ofnot ~~Regulation~~be ~~S-K~~offered or sold in the ~~Proxy~~United States ~~Statement.~~absent ~~This~~registration ~~proposal~~or ~~received~~an applicable exemption from, or in a transaction not subject to, the ~~following~~registration ~~votes:~~requirements of the Securities Act and applicable state securities laws.

For						Against						Abstain						Broker Non-Vote
223,486,130						7,742,108						891,652						29,485,212

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.

AtThe ~~the~~Company ~~Annual~~will ~~Meeting,~~pay ~~the~~6.250% interest ~~Company’s~~per ~~stockholders~~annum ~~ratified~~on the ~~appointment~~principal amount of ~~Deloitte~~the &Notes, ~~Touche~~payable ~~LLP~~semi-annually ason January 15 and July 15 of each year. Interest on the ~~Company’s~~Notes ~~independent~~will ~~registered~~accrue ~~public~~from ~~accounting~~June 26, ~~firm~~2026, ~~for~~and the ~~fiscal~~first ~~year~~interest ~~ending~~payment ~~December~~date 31for the Notes will be January 15, ~~2026~~2027. ~~This~~The Notes ~~proposal~~will ~~received~~mature on January 15, 2035, unless they are earlier redeemed or repurchased in accordance with the ~~following~~terms ~~votes:~~set forth in the Indenture.

For						Against						Abstain
249,250,207						11,947,700						407,195

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 ~~results~~Company ~~reported~~has ~~above~~the ~~are~~option to ~~final~~redeem ~~voting~~all ~~results~~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.

~~Item~~The 8Indenture provides for customary “events of default” which could cause, or permit, the acceleration of the Notes.~~01. Other~~ ~~Events~~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.

~~Committee~~This ~~Appointments~~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.

OnThis ~~May~~Current 7,Report ~~2026,~~on ~~upon~~Form 8-K shall ~~recommendation~~not ~~from~~constitute ~~the~~an ~~Company’s~~offer ~~Nominating~~to ~~and~~sell ~~Governance~~or ~~Committee,~~ the ~~Board~~solicitation of ~~Directors~~an ~~approved~~offer ~~the~~to ~~appointment~~buy ofsecurities, ~~the~~nor ~~following~~shall ~~members~~there be any sale of ~~the~~these ~~Company’s~~securities in ~~Audit,~~any ~~Compensation~~state ~~and~~or ~~Nominating~~other ~~and~~jurisdiction ~~Governance~~in ~~Committees,~~which ~~effective~~such atoffer, ~~the~~solicitation ~~conclusion~~or ofsale ~~the~~would ~~Annual~~be ~~Meeting~~unlawful onprior ~~May~~to 7,registration ~~2026,~~or ~~and~~qualification under ~~subject~~the tosecurities ~~their~~laws ~~re-election~~of atany ~~the~~such ~~Annual~~state ~~Meeting:~~or jurisdiction.

~~Audit~~Item ~~Committee Walter C~~2. ~~Rakowich, Chair Jennifer Allerton Kent P~~03. ~~Dauten~~Creation ~~June~~of ~~Yee~~a ~~Felix~~Direct ~~Christie~~Financial ~~Kelly~~Obligation ~~Compensation~~or ~~Committee~~an ~~Robin~~Obligation L.under ~~Matlock,~~an ~~Chair~~Off-Balance ~~Pamela~~Sheet M.Arrangement ~~Arway~~of ~~Monte~~a ~~Ford Doyle R~~Registrant. ~~Simons Nominating and Governance Committee Theodore R. Samuels, Chair Pamela M. Arway Kent P. Dauten Walter C. Rakowich~~

The ~~Company~~information ~~also~~included ~~has~~in Item ~~a Finance Committee and a Risk and Safety Committee, neither of which are required by the rules of the New York Stock Exchange~~1.01 ~~On May 7, 2026, the Board~~ of ~~Directors,~~this ~~upon~~Current ~~recommendation~~Report ~~from the Nominating and Governance Committee, approved the appointment of the following members to these committees, effective at the conclusion of the Annual Meeting~~ on ~~May~~8-K 7,is ~~2026,~~incorporated ~~and~~into ~~subject~~this toItem ~~their~~2.03 ~~re-election~~by ~~at the Annual Meeting:~~reference.

Finance Committee Doyle R. Simons, Chair Kent P. Dauten Christie Kelly Walter C. Rakowich Theodore R. Samuels

Risk and Safety Committee Monte Ford, Chair Jennifer Allerton June Yee Felix Robin L. Matlock

Item 9.01.

Financial Statements and Exhibits.

(d) Exhibits

101 Cover Page Interactive Data File - the cover page XBRL tags are embedded within the Inline XBRL document.

4.1	Senior Indenture, dated as of June 26, 2026, among the Company, the Subsidiary Guarantors and Computershare Trust Company, N.A., as trustee, relating to the 6.250% Senior Notes due 2035.
104	Cover Page Interactive Data File. (Formatted as Inline XBRL and contained in Exhibit 101.)

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~~ thereunto duly authorized.

IRON MOUNTAIN INCORPORATED By: /s/ ~~Michelle~~Barry ~~Altamura~~Hytinen Name: ~~Michelle~~Barry ~~Altamura~~Hytinen Title: Executive Vice President, ~~General~~and ~~Counsel~~Chief ~~and~~Financial ~~Secretary~~Officer

Date: June ~~May 12~~26, 2026

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