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                                April 1, 2024

       Joe Kiani
       Chief Executive Officer
       Masimo Corporation
       52 Discovery
       Irvine, California

                                                        Re: Masimo Corporation
                                                            DEFA14A filed April 
1, 2024
                                                            File No. 001-33642

       Dear Joe Kiani:

                                                        We have reviewed your 
filing and have the following comment.

               Please respond to this comment by providing the requested 
information or advise us as
       soon as possible when you will respond. If you do not believe our 
comment applies to your facts
       and circumstances, please tell us why in your response.

                                                        After reviewing your 
response to this comment, we may have additional comments.

       DEFA14A filed April 1, 2024

       General

   1.                                                   Communications made in 
reliance on Rule 14a-12 must identify the participants in the
                                                        solicitation and 
describe the participants       direct or indirect interests.    Please note 
that the
                                                        legend must advise 
security holders where they can currently obtain such information,
                                                        which requirement is 
not satisfied by including a general reference to filings made by the
                                                        soliciting party. See 
Rule 14a-12(a)(1)(i) and Question 132.03 of the Compliance and
                                                        Disclosure 
Interpretations for Proxy Rules and Schedules 14A/14C. Please provide this
                                                        information in all 
future soliciting materials.
               We remind you that the filing persons are responsible for the 
accuracy and adequacy of
       their disclosures, notwithstanding any review, comments, action or 
absence of action by the staff.
 Joe Kiani
Masimo Corporation
April 1, 2024
Page 2

      Please direct any questions to Blake Grady at 202-551-8573 or Christina 
Chalk at 202-
551-3263.



FirstName LastNameJoe Kiani                               Sincerely,
Comapany NameMasimo Corporation
                                                          Division of 
Corporation Finance
April 1, 2024 Page 2                                      Office of Mergers & 
Acquisitions
FirstName LastName