Statement of Changes in Beneficial Ownership (Form 4)

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b). Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * Politan Capital Management LP 2. Issuer Name and Ticker or Trading Symbol MASIMO CORP [MASI] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner _____ Officer (give title below) __X__ Other (specify below) Director by deputization (Last) (First) (Middle) 106 WEST 56TH STREET, 10TH FLOOR 3. Date of Earliest Transaction (Month/Day/Year) 04/29/2025 (Street) NEW YORK, NY 10019 4. If Amendment, Date Original Filed (Month/Day/Year) 6. Individual or Joint/Group Filing (Check Applicable Line) ___ Form filed by One Reporting Person _X_ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock, par value $0.001 per share 04/29/2025 M 1,790 A $ 0 4,716,536 I See footnotes(1)(2)(3)(4)(5)

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Restricted Stock Units

(6)

04/29/2025

M

1,790

(7)

09/19/2034

Common Stock

1,790

$ 0

0

I

See footnotes(8)

Restricted Stock Units

(6)

04/29/2025

A

1,225

(9)

04/29/2035

Common Stock

1,225

$ 0

1,225

I

See footnotes(8)

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Politan Capital Management LP 106 WEST 56TH STREET 10TH FLOOR NEW YORK, NY 10019				Director by deputization
Politan Capital Management GP LLC 106 WEST 56TH STREET 10TH FLOOR NEW YORK, NY 10019				Director by deputization
Politan Capital Partners GP LLC 106 WEST 56TH STREET 10TH FLOOR NEW YORK, NY 10019				Director by deputization
Koffey Quentin 106 WEST 56TH STREET 10TH FLOOR NEW YORK, NY 10019	X

Signatures

Politan Capital Management LP By: Politan Capital Management GP LLC, its General Partner /s/ Quentin Koffey, Managing Member		05/01/2025
**Signature of Reporting Person		Date
Politan Capital Management GP LLC /s/ Quentin Koffey, Managing Member		05/01/2025
**Signature of Reporting Person		Date
Politan Capital Partners GP LLC /s/ Quentin Koffey, Managing Member		05/01/2025
**Signature of Reporting Person		Date
/s/ Quentin Koffey		05/01/2025
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	In addition to Politan Capital Management LP, a Delaware limited partnership ("Politan"), this Form 4 is being filed jointly by Politan Capital Management GP LLC, a Delaware limited liability company ("Politan Management"), Politan Capital Partners GP LLC, a Delaware limited liability company ("Politan GP"), and Quentin Koffey, a citizen of the United States of America (together with Politan, Politan Management and Politan GP, the "Reporting Persons"), each of whom has the same business address as Politan and may be deemed to have a pecuniary interest in securities reported on this Form 4 (the "Subject Securities").
(2)	Politan is the investment advisor to certain funds, including Politan Capital Partners LP, a Delaware limited partnership ("Politan LP"), Politan Capital Offshore Partners LP, a Cayman Islands exempted limited partnership ("Politan Offshore"), and Politan Capital Partners Master Fund LP, a Cayman Islands exempted limited partnership ("Politan Master Fund") (collectively with Politan Offshore and Politan LP, the "Politan Funds").
(3)	Politan, as the investment advisor of the Politan Funds, may be deemed to be the beneficial owner of the Subject Securities for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934. As the general partner of Politan, Politan Management may be deemed to be the beneficial owner of the Subject Securities for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934. As the general partner of the Politan Funds, Politan GP may be deemed to be the beneficial owner of the Subject Securities for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934.
(4)	By virtue of Mr. Koffey's position as managing partner and chief investment officer of Politan, and as the managing member of Politan Management and Politan GP, Mr. Koffey may be deemed to be the beneficial owner of the Subject Securities for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934. Each of the Reporting Persons disclaims any beneficial ownership of any of the Subject Securities, except to the extent of any pecuniary interest therein.
(5)	Mr. Koffey is a member of the board of directors of the Issuer of the Subject Securities, and as a result, each of the other Reporting Persons may be directors by deputization for purposes of Section 16 of the Securities Exchange Act of 1934.
(6)	Each restricted stock unit ("RSU") represents the contingent right to receive one share of Common Stock of the Issuer upon vesting of the RSU.
(7)	These RSUs were granted on September 19, 2024 and vested in full on April 29, 2025, the date of the next annual meeting of stockholders following the date of the grant.
(8)	These RSUs are held directly by Mr. Koffey.
(9)	These RSUs were granted on April 29, 2025 and will vest in full on the earlier of the first anniversary of the grant date or the date of the next annual meeting of stockholders following the grant.

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