<SEC-DOCUMENT>0001144204-15-040835-index.html : 20150702
<SEC-HEADER>0001144204-15-040835.hdr.sgml : 20150702
<ACCEPTANCE-DATETIME>20150702161254
ACCESSION NUMBER:		0001144204-15-040835
CONFORMED SUBMISSION TYPE:	SC 13G/A
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20150702
DATE AS OF CHANGE:		20150702

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			NxStage Medical, Inc.
		CENTRAL INDEX KEY:			0001333170
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTROMEDICAL & ELECTROTHERAPEUTIC APPARATUS [3845]
		IRS NUMBER:				043454702
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-81212
		FILM NUMBER:		15969896

	BUSINESS ADDRESS:	
		STREET 1:		350 MERRIMACK STREET
		CITY:			LAWRENCE
		STATE:			MA
		ZIP:			01843
		BUSINESS PHONE:		978-687-4700

	MAIL ADDRESS:	
		STREET 1:		350 MERRIMACK STREET
		CITY:			LAWRENCE
		STATE:			MA
		ZIP:			01843

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			BLAIR WILLIAM & CO/IL
		CENTRAL INDEX KEY:			0000902367
		STANDARD INDUSTRIAL CLASSIFICATION:	UNKNOWN SIC - 0000 [0000]
		IRS NUMBER:				362214610
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G/A

	BUSINESS ADDRESS:	
		STREET 1:		222 WEST ADAMS ST
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606-5312
		BUSINESS PHONE:		3122361600

	MAIL ADDRESS:	
		STREET 1:		222 WEST ADAMS
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606
</SEC-HEADER>
<DOCUMENT>
<TYPE>SC 13G/A
<SEQUENCE>1
<FILENAME>v414726_sc13ga.htm
<DESCRIPTION>SCHEDULE 13G AMENDMENT NO. 4
<TEXT>
Document 1 - file: v414726_sc13ga.htm

</DOCUMENT>
</SEC-DOCUMENT>