<SEC-DOCUMENT>0001020569-23-000088.txt : 20230313
<SEC-HEADER>0001020569-23-000088.hdr.sgml : 20230313
<ACCEPTANCE-DATETIME>20230313163747
ACCESSION NUMBER:		0001020569-23-000088
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20230309
FILED AS OF DATE:		20230313
DATE AS OF CHANGE:		20230313

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Meaney William L
		CENTRAL INDEX KEY:			0001566391

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13045
		FILM NUMBER:		23727801

	MAIL ADDRESS:	
		STREET 1:		C/O IRON MOUNTAIN INCORPORATED
		STREET 2:		ONE FEDERAL STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02110

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			IRON MOUNTAIN INC
		CENTRAL INDEX KEY:			0001020569
		STANDARD INDUSTRIAL CLASSIFICATION:	REAL ESTATE INVESTMENT TRUSTS [6798]
		IRS NUMBER:				232588479
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		85 NEW HAMPSHIRE AVENUE, SUITE 150
		STREET 2:		PEASE INTERNATIONAL TRADEPORT
		CITY:			PORTSMOUTH
		STATE:			NH
		ZIP:			03801
		BUSINESS PHONE:		617-535-4781

	MAIL ADDRESS:	
		STREET 1:		ONE FEDERAL STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02110

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	IRON MOUNTAIN INC/PA
		DATE OF NAME CHANGE:	20000201

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	PIERCE LEAHY CORP
		DATE OF NAME CHANGE:	19960807
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_167873985475852.xml
<DESCRIPTION>FORM 4
<TEXT>
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        <issuerName>IRON MOUNTAIN INC</issuerName>
        <issuerTradingSymbol>IRM</issuerTradingSymbol>
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        <reportingOwnerId>
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            <rptOwnerName>Meaney William L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O IRON MOUNTAIN INCORPORATED</rptOwnerStreet1>
            <rptOwnerStreet2>85 NEW HAMPSHIRE AVENUE, SUITE 150</rptOwnerStreet2>
            <rptOwnerCity>PORTSMOUTH</rptOwnerCity>
            <rptOwnerState>NH</rptOwnerState>
            <rptOwnerZipCode>03801</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President and CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

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                <value>Common Stock, par value $.01 per share</value>
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            <transactionDate>
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            <transactionCoding>
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                <equitySwapInvolved>0</equitySwapInvolved>
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                <equitySwapInvolved>0</equitySwapInvolved>
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                    <value>782</value>
                </transactionShares>
                <transactionPricePerShare>
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                <transactionAcquiredDisposedCode>
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                <sharesOwnedFollowingTransaction>
                    <value>307410</value>
                </sharesOwnedFollowingTransaction>
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                <directOrIndirectOwnership>
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        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $.01 per share</value>
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            <transactionDate>
                <value>2023-03-09</value>
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            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F3"/>
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                <transactionShares>
                    <value>11760</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>52.65</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
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                <sharesOwnedFollowingTransaction>
                    <value>295650</value>
                </sharesOwnedFollowingTransaction>
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                <directOrIndirectOwnership>
                    <value>D</value>
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        </nonDerivativeTransaction>
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    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Performance Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
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            <transactionDate>
                <value>2023-03-09</value>
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                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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                <transactionShares>
                    <value>17192</value>
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                <transactionPricePerShare>
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                <footnoteId id="F5"/>
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            <expirationDate>
                <footnoteId id="F5"/>
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                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
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                    <value>17192.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
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                <sharesOwnedFollowingTransaction>
                    <value>17192</value>
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                <transactionCode>M</transactionCode>
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                </transactionShares>
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                <underlyingSecurityShares>
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                    <value>D</value>
                </directOrIndirectOwnership>
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        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
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                    <value>2115</value>
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                    <value>D</value>
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                <footnoteId id="F8"/>
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                <underlyingSecurityTitle>
                    <value>Common Stock</value>
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    <footnotes>
        <footnote id="F1">This acquisition is reported to reflect the full vesting of performance units (&quot;PUs&quot;) previously granted to the Reporting Person on March 9, 2020. Effective February 23, 2023, the Compensation Committee of Iron Mountain Incorporated's Board of Directors (the &quot;Compensation Committee&quot;) determined the actual award of PUs under the grant after completion of the relevant performance period, and the PUs vested in full on March 9, 2023.</footnote>
        <footnote id="F2">This acquisition is reported to reflect the partial vesting of restricted stock units (&quot;RSUs&quot;) previously granted to the Reporting Person on March 9, 2020.</footnote>
        <footnote id="F3">This transaction was effected pursuant to a 10b5-1 trading plan which was approved and became effective as of May 20, 2022.</footnote>
        <footnote id="F4">Each PU represents a contingent right to receive one share of Iron Mountain Incorporated common stock (&quot;Common Stock&quot;).</footnote>
        <footnote id="F5">The PUs were initially granted to the Reporting Person on March 9, 2020 and fully vested on March 9, 2023.</footnote>
        <footnote id="F6">The PUs were initially granted to the Reporting Person on March 9, 2020. Effective February 23, 2023, the Compensation Committee determined the actual award of PUs under the grant after completion of the relevant performance period, and the PUs vested in full on March 9, 2023.</footnote>
        <footnote id="F7">Each RSU represents a contingent right to receive one share of Iron Mountain Incorporated Common Stock.</footnote>
        <footnote id="F8">The RSUs, representing a contingent right to receive a total of 6,345 shares of Common Stock, were granted to the Reporting Person on March 9, 2020 and are fully vested.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Elizabeth Tammaro, under Power of Attorney dated May 26, 2016, from William Meaney</signatureName>
        <signatureDate>2023-03-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
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</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
