<SEC-DOCUMENT>0000899243-23-014140.txt : 20230530
<SEC-HEADER>0000899243-23-014140.hdr.sgml : 20230530
<ACCEPTANCE-DATETIME>20230530215500
ACCESSION NUMBER:		0000899243-23-014140
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20230525
FILED AS OF DATE:		20230530
DATE AS OF CHANGE:		20230530

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BCIP Life Sciences Associates, LP
		CENTRAL INDEX KEY:			0001702921
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39402
		FILM NUMBER:		23978786

	BUSINESS ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		6175162878

	MAIL ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Bain Capital Life Sciences Fund, L.P.
		CENTRAL INDEX KEY:			0001687968
		STATE OF INCORPORATION:			E9
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39402
		FILM NUMBER:		23978788

	BUSINESS ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		617-516-2000

	MAIL ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Bain Capital Life Sciences Investors, LLC
		CENTRAL INDEX KEY:			0001703031
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39402
		FILM NUMBER:		23978789

	BUSINESS ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		6175162878

	MAIL ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Bain Capital Life Sciences Partners, LP
		CENTRAL INDEX KEY:			0001703030
		STATE OF INCORPORATION:			E9
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39402
		FILM NUMBER:		23978787

	BUSINESS ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		6175162878

	MAIL ADDRESS:	
		STREET 1:		200 CLARENDON STREET
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Annexon, Inc.
		CENTRAL INDEX KEY:			0001528115
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				275414423
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1400 SIERRA POINT PARKWAY
		STREET 2:		BLDG C, SUITE 200
		CITY:			BRISBANE
		STATE:			CA
		ZIP:			94005
		BUSINESS PHONE:		(650)-822-5500

	MAIL ADDRESS:	
		STREET 1:		1400 SIERRA POINT PARKWAY
		STREET 2:		BLDG C, SUITE 200
		CITY:			BRISBANE
		STATE:			CA
		ZIP:			94005
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>doc3.xml
<DESCRIPTION>FORM 3 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2023-05-25</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001528115</issuerCik>
        <issuerName>Annexon, Inc.</issuerName>
        <issuerTradingSymbol>ANNX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001703031</rptOwnerCik>
            <rptOwnerName>Bain Capital Life Sciences Investors, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>200 CLARENDON STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001687968</rptOwnerCik>
            <rptOwnerName>Bain Capital Life Sciences Fund, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>200 CLARENDON STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001703030</rptOwnerCik>
            <rptOwnerName>Bain Capital Life Sciences Partners, LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>200 CLARENDON STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001702921</rptOwnerCik>
            <rptOwnerName>BCIP Life Sciences Associates, LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>200 CLARENDON STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5401926</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                    <footnoteId id="F8"/>
                    <footnoteId id="F9"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Warrant (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>5.8069</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2022-07-11</value>
            </exerciseDate>
            <expirationDate>
                <value>2025-06-30</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>774943</value>
                    <footnoteId id="F4"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                    <footnoteId id="F8"/>
                    <footnoteId id="F9"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Pre-Funded Warrant (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.001</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2022-07-11</value>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F5"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2739475</value>
                    <footnoteId id="F4"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                    <footnoteId id="F8"/>
                    <footnoteId id="F9"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Represents 2,940,627 shares of Common Stock held by Bain Capital Life Sciences Fund, L.P. (&quot;BCLS Fund I&quot;), 2,160,298 shares of Common Stock held by BCLS I Investco, LP (&quot;BCLS I Investco&quot;) and 301,001 shares of Common Stock held by BCIP Life Sciences Associates, LP (&quot;BCIPLS&quot; and, together with BCLS Fund I and BCLS I Investco, the &quot;Bain Capital Life Sciences Entities&quot;).</footnote>
        <footnote id="F2">Represents a warrant to purchase 774,943 shares of Common Stock held by BCLS I Investco.</footnote>
        <footnote id="F3">Represents a pre-funded warrant to purchase 2,739,475 shares of Common Stock held by BCLS I Investco.</footnote>
        <footnote id="F4">BCLS I Investco is prohibited from exercising the warrant to purchase Common Stock referred to in footnote (2) above or the pre-funded warrant to purchase Common Stock referred to in footnote (3) above if the Bain Capital Life Sciences Entities would, in the aggregate, beneficially own more than 9.99% of the total number of shares of Common Stock then issued and outstanding immediately after giving effect to such exercise.</footnote>
        <footnote id="F5">The pre-funded warrant does not expire.</footnote>
        <footnote id="F6">Bain Capital Life Sciences Partners, LP (&quot;BCLSP&quot;) is the general partner of BCLS Fund I. As a result, BCLSP may be deemed to share voting and dispositive power with respect to the securities held by BCLS Fund I. BCLSP disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.</footnote>
        <footnote id="F7">BCLS I Investco GP, LLC (&quot;BCLS I Investco GP&quot;), whose manager is BCLS Fund I, is the general partner of BCLS I Investco. As a result, each of BCLSP, BCLS Fund I and BCLS I Investco GP may be deemed to share voting and dispositive power with respect to the securities held by BCLS I Investco. Each of BCLSP, BCLS Fund I and BCLS I Investco GP disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.</footnote>
        <footnote id="F8">Boylston Coinvestors, LLC is the general partner of BCIPLS.</footnote>
        <footnote id="F9">Bain Capital Life Sciences Investors, LLC (&quot;BCLSI&quot;) is the general partner of BCLSP and governs the investment strategy and decision making process with respect to investments held by BCIPLS. As a result, BCLSI may be deemed to share voting and dispositive power with respect to the securities held by the Bain Capital Life Sciences Entities. BCLSI disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Bain Capital Life Sciences Investors, LLC, By: /s/ Ricky Sun, Title: Partner</signatureName>
        <signatureDate>2023-05-30</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Bain Capital Life Sciences Fund, L.P., By: Bain Capital Life Sciences Partners, LP, its general partner, By: Bain Capital Life Sciences Investors, LLC, its general partner, By: /s/ Ricky Sun, Title: Partner</signatureName>
        <signatureDate>2023-05-30</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>Bain Capital Life Sciences Partners, LP, By: Bain Capital Life Sciences Investors, LLC, its general partner, By: /s/ Ricky Sun, Title: Partner</signatureName>
        <signatureDate>2023-05-30</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>BCIP Life Sciences Associates, LP, By: Boylston Coinvestors, LLC, its general partner, By: /s/ Ricky Sun, Title: Authorized Signatory</signatureName>
        <signatureDate>2023-05-30</signatureDate>
    </ownerSignature>
</ownershipDocument>
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</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
