<SEC-DOCUMENT>0001213900-21-009785.txt : 20210216
<SEC-HEADER>0001213900-21-009785.hdr.sgml : 20210216
<ACCEPTANCE-DATETIME>20210216190311
ACCESSION NUMBER:		0001213900-21-009785
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210211
FILED AS OF DATE:		20210216
DATE AS OF CHANGE:		20210216

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Mastrangelo Joe
		CENTRAL INDEX KEY:			0001833309

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39291
		FILM NUMBER:		21641826

	MAIL ADDRESS:	
		STREET 1:		199 PIERCE STREET, SUITE 537
		CITY:			FRANKLIN TOWNSHIP
		STATE:			NJ
		ZIP:			08873

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Eos Energy Enterprises, Inc.
		CENTRAL INDEX KEY:			0001805077
		STANDARD INDUSTRIAL CLASSIFICATION:	MISCELLANEOUS ELECTRICAL MACHINERY, EQUIPMENT & SUPPLIES [3690]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		3920 PARK AVENUE
		CITY:			EDISON
		STATE:			NJ
		ZIP:			08820
		BUSINESS PHONE:		(732) 225-8400

	MAIL ADDRESS:	
		STREET 1:		3920 PARK AVENUE
		CITY:			EDISON
		STATE:			NJ
		ZIP:			08820

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	B. Riley Principal Merger Corp. II
		DATE OF NAME CHANGE:	20200227
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>ownership.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-02-11</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001805077</issuerCik>
        <issuerName>Eos Energy Enterprises, Inc.</issuerName>
        <issuerTradingSymbol>EOSE</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001833309</rptOwnerCik>
            <rptOwnerName>Mastrangelo Joe</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O EOS ENERGY ENTERPRISES, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>3920 PARK AVENUE</rptOwnerStreet2>
            <rptOwnerCity>EDISON</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>08820</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Executive Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-02-11</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>5015</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>79546</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Common Stock grant in connection with the issuer's achievement of certain performance targets.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Joe Mastrangelo</signatureName>
        <signatureDate>2021-02-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
