[Form 4] Masimo Corporation Insider Trading Activity

Rhea-AI Filing Summary

Politan Capital and affiliated entities disclosed a Form 4 reporting an internal distribution of Masimo Corporation (MASI) shares. On 08/29/2025 the Reporting Persons recorded a Code J(1) transaction showing 126,888 shares disposed at a reported price of $0, with an explanatory footnote stating those shares were distributed to a limited partner and were not sold in the open market. After the reported distribution, the Reporting Persons collectively beneficially owned 4,589,648 shares on an indirect basis. The filing is joint by Politan Capital Management LP, its GP entities, and Quentin Koffey, who is identified as a director and managing partner; signatures are dated 08/29/2025.

Positive

• Transaction was a distribution to a limited partner, not an open-market sale
• Reporting Persons retain a substantial indirect stake of 4,589,648 shares
• Filing discloses relationships and potential beneficial ownership clearly

Negative

• Reported decrease of 126,888 shares in holdings due to the distribution

Insights

Financial Analyst

TL;DR: Internal reallocation reduced reported holdings by 126,888 shares; core stake remains sizable at 4.59M shares.

The Form 4 shows a distribution to a limited partner rather than an open-market sale, which implies no immediate market pressure from these shares. Reporting Persons continue to hold a material indirect stake of 4,589,648 shares. The filing clarifies beneficial ownership through investment adviser and GP relationships, consistent with fund administration mechanics. This is a routine liquidity/ownership reallocation within affiliated fund structures rather than a change in investment stance evident from public transactions.

Corporate Governance Expert

TL;DR: Disclosure correctly identifies relationships and potential deputized director status; transaction is an internal distribution.

The filing discloses interrelated reporting persons and explains why each may be deemed a beneficial owner under Rule 16a-1(a). It also notes Mr. Quentin Koffey's board membership and management roles, and that other entities may be "directors by deputization." Signatures from each reporting party are provided with the same transaction date, meeting filing formalities. Procedurally, the Form 4 supplies required detail for investor transparency about ownership shifts within affiliated accounts.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

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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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 for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Politan Capital Management LP

(Last) (First) (Middle)

106 WEST 56TH STREET

10TH FLOOR

(Street)

NEW YORK NY 10019

(City) (State) (Zip)

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

3. Date of Earliest Transaction (Month/Day/Year)
08/29/2025

4. If Amendment, Date of 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

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	08/29/2025		J(1)		126,888	D(1)	$0	4,589,648	I	See footnotes(2)(3)(4)(5)(6)

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 Securities Underlying Derivative Security (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: 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

1. Name and Address of Reporting Person^*

Politan Capital Management LP

(Last) (First) (Middle)

106 WEST 56TH STREET

10TH FLOOR

(Street)

NEW YORK NY 10019

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

	Director		10% Owner
	Officer (give title below)	X	Other (specify below)
			Director by deputization

1. Name and Address of Reporting Person^*

Politan Capital Management GP LLC

(Last) (First) (Middle)

106 WEST 56TH STREET

10TH FLOOR

(Street)

NEW YORK NY 10019

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

	Director		10% Owner
	Officer (give title below)	X	Other (specify below)
			Director by deputization

1. Name and Address of Reporting Person^*

Politan Capital Partners GP LLC

(Last) (First) (Middle)

106 WEST 56TH STREET

10TH FLOOR

(Street)

NEW YORK NY 10019

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

	Director		10% Owner
	Officer (give title below)	X	Other (specify below)
			Director by deputization

1. Name and Address of Reporting Person^*

Koffey Quentin

(Last) (First) (Middle)

106 WEST 56TH STREET

10TH FLOOR

(Street)

NEW YORK NY 10019

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

Explanation of Responses:

1. The Reporting Persons (as defined below) distributed these shares to a limited partner - no shares were sold in the open market or otherwise.

2. 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").

3. 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").

4. 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.

5. 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.

6. 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.

	Politan Capital Management LP By: Politan Capital Management GP LLC, its General Partner /s/ Quentin Koffey, Managing Member	08/29/2025
	Politan Capital Management GP LLC /s/ Quentin Koffey, Managing Member	08/29/2025
	Politan Capital Partners GP LLC /s/ Quentin Koffey, Managing Member	08/29/2025
	/s/ Quentin Koffey	08/29/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What transaction did Politan report on the MASI Form 4?

The Form 4 reports a Code J(1) transaction on 08/29/2025 showing 126,888 shares disposed with a reported price of $0, described as a distribution to a limited partner.

How many MASI shares do the Reporting Persons beneficially own after the transaction?

After the reported transaction the Reporting Persons beneficially owned 4,589,648 shares on an indirect basis.

Who are the Reporting Persons named on the Form 4 for MASI?

The Form 4 is filed jointly by Politan Capital Management LP, Politan Capital Management GP LLC, Politan Capital Partners GP LLC, and Quentin Koffey.

Was the distributed stock sold in the open market?

No; the filing explicitly states the shares were distributed to a limited partner and no shares were sold in the open market.

What roles does Quentin Koffey hold according to the filing?

The filing identifies Quentin Koffey as a managing partner and chief investment officer of Politan, managing member of the GP entities, and a member of Masimo's board of directors.