<SEC-DOCUMENT>0001209191-21-042858.txt : 20210623
<SEC-HEADER>0001209191-21-042858.hdr.sgml : 20210623
<ACCEPTANCE-DATETIME>20210623202758
ACCESSION NUMBER:		0001209191-21-042858
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210621
FILED AS OF DATE:		20210623
DATE AS OF CHANGE:		20210623

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Rhodes Jason P
		CENTRAL INDEX KEY:			0001577014

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39319
		FILM NUMBER:		211040214

	MAIL ADDRESS:	
		STREET 1:		C/O EPIZYME, INC.
		STREET 2:		400 TECHNOLOGY SQUARE, 4TH FLOOR
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Generation Bio Co.
		CENTRAL INDEX KEY:			0001733294
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				814301281
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		301 BINNEY STREET
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142
		BUSINESS PHONE:		857-529-5908

	MAIL ADDRESS:	
		STREET 1:		301 BINNEY STREET
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
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        <issuerName>Generation Bio Co.</issuerName>
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            <rptOwnerState>MA</rptOwnerState>
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        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
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            <transactionDate>
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                <value></value>
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            <transactionAmounts>
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                    <value>See footnote</value>
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                    <footnoteId id="F6"/>
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                    <footnoteId id="F6"/>
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                <directOrIndirectOwnership>
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                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F7"/>
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                    <footnoteId id="F6"/>
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                    <footnoteId id="F11"/>
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                    <footnoteId id="F6"/>
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                <directOrIndirectOwnership>
                    <value>I</value>
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                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F7"/>
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                <value>Common Stock</value>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F12"/>
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        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
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                <directOrIndirectOwnership>
                    <value>I</value>
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                <natureOfOwnership>
                    <value>See footnote</value>
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    <footnotes>
        <footnote id="F1">Shares were sold pursuant to a Rule 10b5-1 trading plan dated April 20 ,2021.</footnote>
        <footnote id="F2">The shares reported herein give effect to the pro rata distribution of shares by Atlas Venture Fund X, L.P. (&quot;Atlas Venture Fund X&quot;) for no additional consideration to its limited partners and its and general partner, Atlas Venture Associates X, L.P. (&quot;AVA X LP&quot;), subsequent to the Reporting Persons' last Section 16 filing reporting ownership of the Issuer's Common Stock. As the distribution of such shares constituted only a change in the form of the Reporting Persons' ownership in such shares, the Reporting Persons were not required to report the distribution pursuant to Section 16.</footnote>
        <footnote id="F3">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $24.08 to $25.07 inclusive. The Reporting Persons undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (3), (5), (8), (9), (10) and (11).</footnote>
        <footnote id="F4">The shares are held directly by AVA X LP. Atlas Venture Associates X, LLC (&quot;AVA X LLC&quot;) is the general partner of AVA X LP. The Reporting Person is a member of AVA X LLC and disclaims Section 16 beneficial ownership of such securities held by AVA X LP, except to the extent of his pecuniary interest therein, if any.</footnote>
        <footnote id="F5">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $25.08 to $25.20 inclusive.</footnote>
        <footnote id="F6">The shares reported herein give effect to the pro rata distribution of shares by Atlas Venture Opportunity Fund I, L.P. (&quot;AVOF I&quot;) for no additional consideration to its limited partners and its and general partner, Atlas Venture Associates Opportunity I, LP (&quot;AVAO LP&quot;), subsequent to the Reporting Persons' last Section 16 filing reporting ownership of the Issuer's Common Stock. As the distribution of such shares constituted only a change in the form of the Reporting Persons' ownership in such shares, the Reporting Persons were not required to report the distribution pursuant to Section 16.</footnote>
        <footnote id="F7">The shares are held directly by AVAO LP. Atlas Venture Associates Opportunity I, LLC (&quot;AVAO LLC&quot;) is the general partner of AVAO LP. The Reporting Person is a member of AVAO LLC and disclaims Section 16 beneficial ownership of such securities held by AVOF I, except to the extent of his pecuniary interest therein, if any.</footnote>
        <footnote id="F8">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $24.08 to $25.07 inclusive.</footnote>
        <footnote id="F9">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $25.10 to $25.285 inclusive.</footnote>
        <footnote id="F10">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $24.63 to $25.62 inclusive.</footnote>
        <footnote id="F11">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $25.63 to $25.95 inclusive.</footnote>
        <footnote id="F12">These shares are held directly by Atlas Venture Fund X. The general partner of Atlas Venture Fund X is AVA X LP. AVA X LLC is the general partner of AVA X LP. The Reporting Person is a member of AVA X LLC and disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Fund X, except to the extend if its pecuniary interest therein, if any.</footnote>
        <footnote id="F13">The shares are owned directly by AVOF I. AVAO LP is the general partner of AVOF I. AVAO LLC is the general partner of AVAO LP. The Reporting Person is a member of AVAO LLC and disclaims Section 16 beneficial ownership of such securities held by AVOF I, except to the extent of his pecuniary interest therein, if any.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Ommer Chohan, Attorney-in-Fact</signatureName>
        <signatureDate>2021-06-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
