SEC Form SC 13D/A filed by Masimo Corporation (Amendment)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

(Rule 13d-101)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT

TO RULE 13d-1(a) AND AMENDMENTS THERETO FILED

PURSUANT TO RULE 13d-2(a)

Under the Securities Exchange Act of 1934

(Amendment No. 8)*

Masimo Corporation

(Name of Issuer)

Common Stock, par value $0.001 per share

(Title of Class of Securities)

574795100

(CUSIP Number)

Quentin Koffey

Politan Capital Management LP

106 West 56^th Street, 10^th Floor

New York, New York 10019

646-690-2830

With a copy to:

Richard M. Brand

Cadwalader, Wickersham & Taft LLP

200 Liberty Street

New York, NY 10281

212-504-6000

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

May 8, 2024

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of Rule 13d-1(e), 13d-1(f) or 13d-1(g), check the following box. ¨

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See Rule 13d-7 for other parties to whom copies are to be sent.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

* All percentage calculations set forth herein are based upon the aggregate of 53,085,556 shares of Common Stock outstanding as of March 30, 2024, as reported in the Issuer’s Quarterly Report on Form 10-Q for the period ended March 30, 2024, filed with the Securities and Exchange Commission (the “SEC”) on May 7, 2024 (the “Q1 2024 10-Q”).

* All percentage calculations set forth herein are based upon the aggregate of 53,085,556 shares of Common Stock outstanding as of March 30, 2024, as reported in the Q1 2024 10-Q.

* All percentage calculations set forth herein are based upon the aggregate of 53,085,556 shares of Common Stock outstanding as of March 30, 2024, as reported in the Q1 2024 10-Q.

* Includes Mr. Koffey’s 1,228 restricted share units granted to him on June 26, 2023 by virtue of his position as a director on the Board and that vest upon the earliest of the first anniversary of the grant date, the date of the next annual meeting of stockholders, or a change in control of the Issuer.

** Mr. Koffey’s percentage calculations set forth herein are based upon the aggregate of 53,085,556 shares of Common Stock outstanding as of March 30, 2024, as reported in the Q1 2024 10-Q.

This Amendment No. 8 to Schedule 13D (this “Amendment No. 8”) amends and supplements the Schedule 13D filed on August 16, 2022 (as amended and supplemented through the date of this Amendment No. 8, collectively, the “Schedule 13D”) by the Reporting Persons, relating to the common stock, par value $0.001 per share, of Masimo Corporation, a Delaware corporation (the “Issuer”). Capitalized terms not defined in this Amendment No. 8 shall have the meaning ascribed to them in the Schedule 13D.

The information set forth in response to Item 4 below shall be deemed to be a response to all Items where such information is relevant.

ITEM 4. PURPOSE OF TRANSACTION

Item 4 of the Schedule 13D is hereby amended and supplemented with the following information:

On May 8, 2024, Quentin Koffey, a Reporting Person, submitted a books and records request (the “Demand Letter”) to the Issuer pursuant to Section 220 of the Delaware General Corporation Law, demanding to inspect certain books and records of the Issuer relating to the Issuer’s proposed separation of its consumer business as well as the identity of a joint venture partner that has not yet been disclosed to the full Board.

The Demand Letter is attached hereto as Exhibit 99.10 and is incorporated herein by reference.

*Previously filed.

SIGNATURES

After reasonable inquiry and to the best of each of the undersigned’s knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.

Date: May 8, 2024

INDEX TO EXHIBITS

*Previously filed.