[Form 4] Masimo Corporation Insider Trading Activity

Rhea-AI Filing Summary

Masimo Corporation director William R. Jellison reported an open-market purchase of common stock on 08/11/2025. The Form 4 shows a purchase of 3,000 shares at a weighted average price of $145.98 per share; the reported purchase prices ranged from $145.84 to $146.00. After the transaction the reporting person beneficially owned 4,790 shares, held in a direct form of ownership.

The filing includes an explanation that the reported price is a weighted average of open market trades and the reporting person offers to provide full transaction details on request. The transaction is recorded with code P indicating a purchase; no derivative transactions are reported.

Positive

• Director William R. Jellison purchased 3,000 shares, increasing direct beneficial ownership to 4,790 shares.
• Transaction pricing disclosed with a weighted average of $145.98 and per-trade range of $145.84–$146.00.

Negative

• None.

Insights

Financial Analyst

TL;DR: A director executed an open-market purchase of 3,000 MASI shares at about $146, modest insider buying that increases direct stake to 4,790 shares.

The Form 4 documents an open-market purchase (transaction code "P") of 3,000 common shares on 08/11/2025 with a weighted average price of $145.98 and individual trade prices between $145.84 and $146.00. The purchase raised direct beneficial ownership to 4,790 shares. The filer supplies the weighted-average price and offers to provide detailed trade-level information on request. There are no derivative transactions disclosed.

Corporate Governance Expert

TL;DR: Director-level insider buying recorded; disclosure is routine and complete for an open-market purchase, showing direct ownership increase.

The filing clearly identifies the reporting person as a director and records the acquisition as a direct purchase. It provides the weighted average and the per-trade price range, and reports the resulting beneficial ownership of 4,790 shares. The form contains required explanatory language about the reported weighted average price. No 10b5-1 plan or derivative activity is described in the transaction tables.

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

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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^*

Jellison William R

(Last) (First) (Middle)

C/O MASIMO CORPORATION

52 DISCOVERY

(Street)

IRVINE CA 92618

(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)

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

3. Date of Earliest Transaction (Month/Day/Year)
08/11/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	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	08/11/2025		P		3,000	A	$145.98(1)	4,790	D

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

Explanation of Responses:

1. The price reported in Column 4 represents the weighted average price per share of open market purchase transactions. The actual purchase prices ranged from a low of $145.84 per share to a high of $146.00 per share. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer, or a security holder of the issuer full information regarding the number of shares and prices at which the transactions were effected.

Remarks:

	/s/ Micah W. Young, Attorney-In-Fact	08/12/2025
	** 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 the Masimo (MASI) Form 4 disclose?

The Form 4 reports an open-market purchase (transaction code P) of 3,000 common shares on 08/11/2025.

Who is the reporting person on the MASI Form 4?

The reporting person is William R. Jellison, identified in the filing as a Director.

What price was paid per share in the MASI insider purchase?

The weighted average price reported is $145.98 per share; individual purchase prices ranged from $145.84 to $146.00.

How many MASI shares does the reporting person own after the transaction?

Following the purchase the reporting person beneficially owned 4,790 shares, held directly.

Were any derivative securities reported on the MASI Form 4?

No derivative securities are listed in Table II; only a non-derivative purchase of common stock is reported.