<SEC-DOCUMENT>0001209191-21-026747-index.html : 20210414
<SEC-HEADER>0001209191-21-026747.hdr.sgml : 20210414
<ACCEPTANCE-DATETIME>20210414201904
ACCESSION NUMBER:		0001209191-21-026747
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210412
FILED AS OF DATE:		20210414
DATE AS OF CHANGE:		20210414

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Atlas Venture Associates X, LLC
		CENTRAL INDEX KEY:			0001742765
		STATE OF INCORPORATION:			DE

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39319
		FILM NUMBER:		21827007

	BUSINESS ADDRESS:	
		STREET 1:		400 TECH. SQ.
		STREET 2:		10TH FLOOR
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139
		BUSINESS PHONE:		857-201-2700

	MAIL ADDRESS:	
		STREET 1:		400 TECH. SQ.
		STREET 2:		10TH FLOOR
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ATLAS VENTURE ASSOCIATES X, L.P.
		CENTRAL INDEX KEY:			0001742766
		STATE OF INCORPORATION:			DE

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39319
		FILM NUMBER:		21827008

	BUSINESS ADDRESS:	
		STREET 1:		400 TECHNOLOGY SQ.
		STREET 2:		10TH FLOOR
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139
		BUSINESS PHONE:		857-201-2700

	MAIL ADDRESS:	
		STREET 1:		400 TECHNOLOGY SQ.
		STREET 2:		10TH 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>
Document 1 - file: doc4.html

Document 1 - RAW XML: doc4.xml

</DOCUMENT>
</SEC-DOCUMENT>