Masimo (MASI) CFO exercises RSUs, retains shares after tax withholding

Rhea-AI Filing Summary

Masimo Corp executive Micah W. Young reported routine equity compensation activity. On March 11, 2026, he exercised 873 restricted stock units, converting them into 873 shares of common stock at an exercise price of $0.00 per share.

These RSUs are part of a 3,495-unit grant awarded on March 11, 2025, which vests in four equal annual installments; the filing reflects the first 25% vesting. To cover related tax obligations, 471 common shares were withheld by Masimo at a price of $175.47 per share.

Following these transactions, Young directly holds 25,656 shares of Masimo common stock and 2,622 unvested RSUs, indicating he retained the net shares from this vesting rather than selling them in the open market.

Insider Trade Summary

873 shares exercised/converted

Mixed 3 txns

Insider Young Micah W

Role EVP & Chief Financial Officer

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Units	873	$0.00	--
Exercise	Common Stock	873	$0.00	--
Tax Withholding	Common Stock	471	$175.47	$83K

Holdings After Transaction: Restricted Stock Units — 2,622 shares (Direct); Common Stock — 26,127 shares (Direct)

Footnotes (1)

1. As previously reported, the reporting person was granted 3,495 restricted stock units (RSUs) on March 11, 2025 and will vest ratably over four years, 25% of which vested on March 11, 2026. These shares were withheld by the Issuer in order to satisfy certain tax withholding obligations in connection with the issuance of shares upon the vesting of certain RSUs. Each RSU represents the contingent right to receive one share of common stock of the Issuer upon vesting of the RSU.

Form 4 Insider Transactions: What Each Field Means →

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
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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^*

Young Micah W

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	EVP & Chief Financial Officer

3. Date of Earliest Transaction (Month/Day/Year)
03/11/2026

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	03/11/2026		M		873(1)	A	$0	26,127	D
Common Stock	03/11/2026		F		471(2)	D	$175.47	25,656	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
Restricted Stock Units	(3)	03/11/2026		M			873	(1)	03/11/2035	Common Stock	873	$0	2,622	D

Explanation of Responses:

1. As previously reported, the reporting person was granted 3,495 restricted stock units (RSUs) on March 11, 2025 and will vest ratably over four years, 25% of which vested on March 11, 2026.

2. These shares were withheld by the Issuer in order to satisfy certain tax withholding obligations in connection with the issuance of shares upon the vesting of certain RSUs.

3. Each RSU represents the contingent right to receive one share of common stock of the Issuer upon vesting of the RSU.

Remarks:

	/s/ Micah W. Young	03/16/2026
	** 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 insider equity transaction did Masimo (MASI) disclose for Micah W. Young?

Masimo disclosed that EVP & CFO Micah W. Young had 873 restricted stock units vest and convert into 873 common shares. This reflects the first 25% tranche of a 3,495-unit RSU grant awarded on March 11, 2025, vesting over four years.

Did Masimo (MASI) EVP & CFO sell shares in the open market?

The filing shows no open-market sale by EVP & CFO Micah W. Young. Instead, 471 shares of common stock were withheld by Masimo at $175.47 per share solely to satisfy tax withholding obligations related to the RSU vesting and share issuance.

How many Masimo (MASI) shares does Micah W. Young hold after the reported transactions?

After the reported RSU vesting and tax withholding, Micah W. Young directly holds 25,656 shares of Masimo common stock. He also has 2,622 unvested restricted stock units remaining from the original 3,495-unit grant awarded in March 2025.

What are the terms of Micah W. Young’s RSU grant at Masimo (MASI)?

Young was granted 3,495 restricted stock units on March 11, 2025. The grant vests ratably over four years, with 25% vesting on March 11, 2026, and each RSU representing the contingent right to receive one Masimo common share upon vesting.

What was the tax-related share withholding in the Masimo (MASI) insider transaction?

Masimo withheld 471 common shares from Micah W. Young at $175.47 per share. This withholding satisfied certain tax obligations arising from the issuance of common shares upon vesting of his restricted stock units, rather than representing a discretionary market sale.