<SEC-DOCUMENT>0000899243-17-025151-index.html : 20171101
<SEC-HEADER>0000899243-17-025151.hdr.sgml : 20171101
<ACCEPTANCE-DATETIME>20171101195022
ACCESSION NUMBER:		0000899243-17-025151
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20171101
FILED AS OF DATE:		20171101
DATE AS OF CHANGE:		20171101

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Atlas Venture Associates IX, L.P.
		CENTRAL INDEX KEY:			0001671208
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1012

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38266
		FILM NUMBER:		171170367

	BUSINESS ADDRESS:	
		STREET 1:		25 FIRST ST
		STREET 2:		STE 303
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02141
		BUSINESS PHONE:		6175882695

	MAIL ADDRESS:	
		STREET 1:		25 FIRST ST
		STREET 2:		STE 303
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02141

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Atlas Venture Fund IX, L.P.
		CENTRAL INDEX KEY:			0001671219
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1012

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38266
		FILM NUMBER:		171170368

	BUSINESS ADDRESS:	
		STREET 1:		25 FIRST ST
		STREET 2:		STE 303
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02141
		BUSINESS PHONE:		6175882695

	MAIL ADDRESS:	
		STREET 1:		25 FIRST ST
		STREET 2:		STE 303
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02141

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Atlas Venture Associates IX, LLC
		CENTRAL INDEX KEY:			0001671207
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1012

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-38266
		FILM NUMBER:		171170369

	BUSINESS ADDRESS:	
		STREET 1:		25 FIRST ST
		STREET 2:		STE 303
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02141
		BUSINESS PHONE:		6175882695

	MAIL ADDRESS:	
		STREET 1:		25 FIRST ST
		STREET 2:		STE 303
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02141

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Spero Therapeutics, Inc.
		CENTRAL INDEX KEY:			0001701108
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		675 MASSACHUSETTS AVENUE
		STREET 2:		14TH FLOOR
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139
		BUSINESS PHONE:		857-242-1600

	MAIL ADDRESS:	
		STREET 1:		675 MASSACHUSETTS AVENUE
		STREET 2:		14TH FLOOR
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Spero Therapeutics, LLC
		DATE OF NAME CHANGE:	20170316
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>doc3.xml
<DESCRIPTION>FORM 3 SUBMISSION
<TEXT>
Document 1 - file: doc3.html

Document 1 - RAW XML: doc3.xml

</DOCUMENT>
</SEC-DOCUMENT>