<SEC-DOCUMENT>0000812295-18-000012-index.html : 20180206
<SEC-HEADER>0000812295-18-000012.hdr.sgml : 20180206
<ACCEPTANCE-DATETIME>20180206154243
ACCESSION NUMBER:		0000812295-18-000012
CONFORMED SUBMISSION TYPE:	SC 13G/A
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20180206
DATE AS OF CHANGE:		20180206

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MASIMO CORP
		CENTRAL INDEX KEY:			0000937556
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTROMEDICAL & ELECTROTHERAPEUTIC APPARATUS [3845]
		IRS NUMBER:				330368882
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-83497
		FILM NUMBER:		18577504

	BUSINESS ADDRESS:	
		STREET 1:		52 DISCOVERY
		CITY:			IRVINE
		STATE:			CA
		ZIP:			92618
		BUSINESS PHONE:		949-297-7000

	MAIL ADDRESS:	
		STREET 1:		52 DISCOVERY
		CITY:			IRVINE
		STATE:			CA
		ZIP:			92618

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			JANUS CAPITAL MANAGEMENT LLC
		CENTRAL INDEX KEY:			0000812295
		STANDARD INDUSTRIAL CLASSIFICATION:	UNKNOWN SIC - 0000 [0000]
		IRS NUMBER:				753019302
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G/A

	BUSINESS ADDRESS:	
		STREET 1:		151 DETROIT ST.
		CITY:			DENVER
		STATE:			CO
		ZIP:			80206-4805
		BUSINESS PHONE:		3033333863

	MAIL ADDRESS:	
		STREET 1:		151 DETROIT ST.
		CITY:			DENVER
		STATE:			CO
		ZIP:			80206-4805

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	JANUS CAPITAL GROUP INC
		DATE OF NAME CHANGE:	20030103

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	JANUS CAPITAL MANAGEMENT LLC
		DATE OF NAME CHANGE:	20020424

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	JANUS CAPITAL CORP
		DATE OF NAME CHANGE:	19931213
</SEC-HEADER>
<DOCUMENT>
<TYPE>SC 13G/A
<SEQUENCE>1
<FILENAME>masi2102018.txt
<DESCRIPTION>JANUS CAPITAL MANAGEMENT 12/31/17 <5% ANNUAL CLOSEOUT
<TEXT>
Document 1 - file: masi2102018.txt

</DOCUMENT>
</SEC-DOCUMENT>