<SEC-DOCUMENT>0001127602-22-002824.txt : 20220201
<SEC-HEADER>0001127602-22-002824.hdr.sgml : 20220201
<ACCEPTANCE-DATETIME>20220201184100
ACCESSION NUMBER:		0001127602-22-002824
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20220128
FILED AS OF DATE:		20220201
DATE AS OF CHANGE:		20220201

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Yates Lloyd M
		CENTRAL INDEX KEY:			0001311411

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-16189
		FILM NUMBER:		22580685

	MAIL ADDRESS:	
		STREET 1:		1N 2ND ST
		CITY:			HARTSVILLE
		STATE:			SC
		ZIP:			29550

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			NISOURCE INC.
		CENTRAL INDEX KEY:			0001111711
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRIC & OTHER SERVICES COMBINED [4931]
		IRS NUMBER:				352108964
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		801 EAST 86TH AVE
		CITY:			MERRILLVILLE
		STATE:			IN
		ZIP:			46410-6272
		BUSINESS PHONE:		2196475200

	MAIL ADDRESS:	
		STREET 1:		801 EAST 86TH AVE
		CITY:			MERRILLVILLE
		STATE:			IN
		ZIP:			46410-6272

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	NISOURCE INC/DE
		DATE OF NAME CHANGE:	20001103

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	NEW NISOURCE INC
		DATE OF NAME CHANGE:	20000412
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>form4.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2022-01-28</periodOfReport>

    <issuer>
        <issuerCik>0001111711</issuerCik>
        <issuerName>NISOURCE INC.</issuerName>
        <issuerTradingSymbol>NI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001311411</rptOwnerCik>
            <rptOwnerName>Yates Lloyd M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>801 E. 86TH AVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MERRILLVILLE</rptOwnerCity>
            <rptOwnerState>IN</rptOwnerState>
            <rptOwnerZipCode>46410</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2022-01-28</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>30747</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>29.27</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>54106.153</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Each Restricted Stock Unit (&quot;RSU&quot;) represents a contingent right to receive one share of the Company's common stock pursuant to the NiSource Inc. 2020 Omnibus Incentive Plan. Subject to certain forfeiture conditions, the RSUs will 100% vest on February 28, 2025 provided that the reporting person is continuously employed by the Company through and including that date. This award was granted in connection with his appointment as President and CEO effective February 14, 2022.</footnote>
        <footnote id="F2">This amount includes RSUs received pursuant to the dividend equivalent provisions of his director RSU award from May 2021.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Kimberly V. Loies, Attorney-in-Fact</signatureName>
        <signatureDate>2022-02-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
