<SEC-DOCUMENT>0001214659-20-005560.txt : 20200612
<SEC-HEADER>0001214659-20-005560.hdr.sgml : 20200612
<ACCEPTANCE-DATETIME>20200612125120
ACCESSION NUMBER:		0001214659-20-005560
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20200611
FILED AS OF DATE:		20200612
DATE AS OF CHANGE:		20200612

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Seybold William
		CENTRAL INDEX KEY:			0001693980

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39319
		FILM NUMBER:		20959633

	MAIL ADDRESS:	
		STREET 1:		C/O FARALLON CAPITAL MANAGEMENT, L.L.C.
		STREET 2:		ONE MARITIME PLAZA, SUITE 2100
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94111

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Spokes Andrew J M
		CENTRAL INDEX KEY:			0001372968

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39319
		FILM NUMBER:		20959634

	MAIL ADDRESS:	
		STREET 1:		C/O FARALLON CAPITAL MANAGEMENT, L.L.C.
		STREET 2:		ONE MARITIME PLAZA,  SUITE 2100
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94111

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Warren John R.
		CENTRAL INDEX KEY:			0001509711

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39319
		FILM NUMBER:		20959635

	MAIL ADDRESS:	
		STREET 1:		C/O FARALLON CAPITAL MANAGEMENT, L.L.C.
		STREET 2:		ONE MARITIME PLAZA, SUITE 2100
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94111

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			WEHRLY MARK C
		CENTRAL INDEX KEY:			0001245635

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39319
		FILM NUMBER:		20959636

	MAIL ADDRESS:	
		STREET 1:		C/O FARALLON CAPITAL MANAGEMENT, L.L.C.
		STREET 2:		ONE MARITIME PLAZA, SUITE  2100
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94111

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>3
<SEQUENCE>1
<FILENAME>marketforms-49032.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2020-06-11</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001733294</issuerCik>
        <issuerName>Generation Bio Co.</issuerName>
        <issuerTradingSymbol>GBIO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001693980</rptOwnerCik>
            <rptOwnerName>Seybold William</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O FARALLON CAPITAL MANAGEMENT, L.L.C.</rptOwnerStreet1>
            <rptOwnerStreet2>ONE MARITIME PLAZA, SUITE 2100</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94111</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>false</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>true</isTenPercentOwner>
            <isOther>true</isOther>
            <officerTitle></officerTitle>
            <otherText>Member of Group Owning 10%</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001372968</rptOwnerCik>
            <rptOwnerName>Spokes Andrew J M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O FARALLON CAPITAL MANAGEMENT, L.L.C.</rptOwnerStreet1>
            <rptOwnerStreet2>ONE MARITIME PLAZA, SUITE 2100</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94111</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>false</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>true</isTenPercentOwner>
            <isOther>true</isOther>
            <officerTitle></officerTitle>
            <otherText>Managing Member</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001509711</rptOwnerCik>
            <rptOwnerName>Warren John R.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O FARALLON CAPITAL MANAGEMENT, L.L.C.</rptOwnerStreet1>
            <rptOwnerStreet2>ONE MARITIME PLAZA, SUITE 2100</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94111</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>false</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>true</isTenPercentOwner>
            <isOther>true</isOther>
            <officerTitle></officerTitle>
            <otherText>Managing Member</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001245635</rptOwnerCik>
            <rptOwnerName>WEHRLY MARK C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O FARALLON CAPITAL MANAGEMENT, L.L.C.</rptOwnerStreet1>
            <rptOwnerStreet2>ONE MARITIME PLAZA, SUITE 2100</rptOwnerStreet2>
            <rptOwnerCity>SAN FRANCISCO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94111</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>false</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>true</isTenPercentOwner>
            <isOther>true</isOther>
            <officerTitle></officerTitle>
            <otherText>Managing Member</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Series C Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1518819</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Series C Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1518819</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                    <footnoteId id="F8"/>
                    <footnoteId id="F9"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The shares of Series C Preferred Stock of Generation Bio Co. (the &quot;Issuer&quot;) are convertible into shares of Common Stock of the Issuer on a 1.7663-for-one basis without payment of further consideration; are convertible by the holder at any time at the holder's election and convert automatically upon the closing of a qualified public offering by the Issuer; and have no expiration date.</footnote>
        <footnote id="F2">The entities and individuals identified in the footnotes of this Form 3 may be deemed members of a group holding equity securities of the Issuer. The filing of this Form 3 and any statements included herein shall not be deemed to be an admission that such entities and individuals are members of such a group.</footnote>
        <footnote id="F3">Since the number of reporting persons that may be listed on a Form 3 is limited, the entities and individuals identified as reporting persons in these footnotes that are not reporting persons on this Form 3 are filing one or more additional Forms 3 on the date hereof as reporting persons with respect to the securities described herein (each, a &quot;Parallel Form 3&quot;).  Information regarding these entities and individuals is included in this Form 3 for purposes of clarification and convenience only, and is duplicative of the information reported in any Parallel Form 3.</footnote>
        <footnote id="F4">The amount of securities shown in this row is owned directly by Zone Healthcare Holdings, LLC (&quot;ZHH LLC&quot;).</footnote>
        <footnote id="F5">Farallon Capital Management, L.L.C. (the &quot;Management Company&quot;), as the manager of ZHH LLC, may be deemed to be a beneficial owner of the Issuer's securities held by ZHH LLC.  The Management Company disclaims any beneficial ownership of any of the Issuer's securities reported or noted herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended (the &quot;'34 Act&quot;), or otherwise, except to the extent of its pecuniary interest, if any.</footnote>
        <footnote id="F6">The members of ZHH LLC are FCP SS 2019, LLC (&quot;FCP SS&quot;), FCIP SS 2019, LLC (&quot;FCIP SS&quot;), FCOI II SS 2019, Ltd. (&quot;FCOI II SS&quot;), Farallon Capital Institutional Partners, II, L.P. (&quot;FCIP II&quot;), Farallon Capital Institutional Partners III, L.P. (&quot;FCIP III&quot;), Four Crossings Institutional Partners V, L.P. (&quot;FCIP V&quot;), Farallon Special Situation Partners VI, L.P. (&quot;FSSP VI&quot;) and Farallon Special Situations Fund, L.P. (&quot;FSSF&quot;).  Each such member of ZHH LLC disclaims any beneficial ownership of any of the Issuer's securities reported or noted herein for purposes of Section 16 of the '34 Act or otherwise.</footnote>
        <footnote id="F7">The sole member of FCP SS is Farallon Capital Partners, L.P. (&quot;FCP&quot;).  The sole member of FCIP SS is Farallon Capital Institutional Partners, L.P. (&quot;FCIP&quot;).  The sole member of FCOI II SS is Farallon Capital Offshore Investors II, L.P. (&quot;FCOI II&quot;).  Each of FCP, FCIP and FCOI II disclaims any beneficial ownership of any of the Issuer's securities reported or noted herein for purposes of Section 16 of the '34 Act or otherwise.</footnote>
        <footnote id="F8">Farallon Partners, L.L.C. (the &quot;Farallon General Partner&quot;), as the general partner of each of FCP, FCIP, FCIP II, FCIP III and FCOI II, the sole member of the respective general partners of FCIP V and FSSP VI and the sole member of the director of FCOI II SS, may be deemed to be a beneficial owner of  the Issuer's securities held indirectly by each of FCP, FCIP,  FCIP II, FCIP III , FCOI II, FCIP V and FSSP VI.  The Farallon General Partner disclaims any beneficial ownership of any of the Issuer's securities reported or noted herein for purposes of Section 16 of the '34 Act, or otherwise, except to the extent of its pecuniary interest, if any.</footnote>
        <footnote id="F9">Each of Philip D. Dreyfuss, Michael B. Fisch, Richard B. Fried, David T. Kim, Michael G. Linn, Rajiv A. Patel, Thomas G. Roberts, Jr., William Seybold, Andrew J. M. Spokes, John R. Warren,  and Mark C. Wehrly (collectively, the &quot;Managing Members&quot;), as a managing member or senior managing member, as the case may be, of the Management Company and the Farallon General Partner, and a manager or senior manager, as the case may be, of the respective general partners of FCIP V, FSSP VI and FSSF, in each case with the power to exercise investment discretion, may be deemed to be a beneficial owner of the Issuer's securities held by ZHH LLC.  Each of the Managing Members disclaims any beneficial ownership of any of the Issuer's securities reported or noted herein for purposes of Section 16 of the '34 Act or otherwise, except to the extent of his pecuniary interest, if any.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Michael B. Fisch, as attorney-in-fact for William Seybold</signatureName>
        <signatureDate>2020-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Michael B. Fisch, as attorney-in-fact for Andrew J. M. Spokes</signatureName>
        <signatureDate>2020-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Michael B. Fisch, as attorney-in-fact for John R. Warren</signatureName>
        <signatureDate>2020-06-11</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Michael B. Fisch, as attorney-in-fact for Mark C. Wehrly</signatureName>
        <signatureDate>2020-06-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
