Masimo (MASI) CHRO nets RSU shares after tax-withholding share disposition

Filing Impact

(Neutral)

Filing Sentiment

(Neutral)

Form Type

Rhea-AI Filing Summary

Masimo Corp Chief Human Resources Officer Elisabeth A. Hellmann reported routine equity compensation activity involving restricted stock units. On April 21, 2026, 335 restricted stock units granted on April 21, 2025 vested, converting into 335 shares of common stock. In connection with this vesting, 121 shares of common stock were withheld by Masimo to cover tax withholding obligations at a price of $178.43 per share, a non-market disposition. Following these transactions, Hellmann directly holds 214 shares of common stock and 1,005 restricted stock units, each representing the contingent right to receive one Masimo common share upon future vesting.

Insider Trade Summary

335 shares exercised/converted

Mixed 3 txns

Insider Hellmann Elisabeth A

Role Chief Human Resources Officer

Type	Security	Shares	Price	Value
Exercise	Restricted Stock Units	335	$0.00	--
Exercise	Common Stock	335	$0.00	--
Tax Withholding	Common Stock	121	$178.43	$22K

Holdings After Transaction: Restricted Stock Units — 1,005 shares (Direct, null); Common Stock — 335 shares (Direct, null)

Footnotes (1)

As previously reported, the reporting person was granted 1,340 restricted stock units (RSUs) on April 21, 2025 and will vest ratably over four years, 25% of which vested on April 21, 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 performance restricted stock units. Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of the Issuer upon vesting of the RSU.

Key Figures

RSUs vested: 335 units Shares withheld for taxes: 121 shares at $178.43 Common shares after transaction: 214 shares +3 more

6 metrics

RSUs vested 335 units Portion of 1,340 RSUs vesting on April 21, 2026

Shares withheld for taxes 121 shares at $178.43 Tax withholding on RSU vesting

Common shares after transaction 214 shares Direct holdings following Form 4 transactions

RSUs remaining 1,005 units Restricted stock units outstanding after April 21, 2026

Original RSU grant 1,340 units Granted April 21, 2025, vesting ratably over four years

Derivative expiration April 21, 2035 Expiration date for the RSU award in the derivative table

Key Terms

restricted stock units (RSUs), tax withholding obligations, performance restricted stock units, derivative security, +1 more

5 terms

restricted stock units (RSUs) financial

"the reporting person was granted 1,340 restricted stock units (RSUs) on April 21, 2025"

Restricted stock units (RSUs) are a type of company promise to give employees shares of stock in the future, usually after certain conditions like working for a set time. They are like a gift promised today that you receive later, which can become valuable if the company's stock price goes up. RSUs matter because they are a way companies reward employees and can be a significant part of compensation.

tax withholding obligations financial

"withheld by the Issuer in order to satisfy certain tax withholding obligations in connection with the issuance"

performance restricted stock units financial

"in connection with the issuance of shares upon the vesting of certain performance restricted stock units"

Performance restricted stock units (PRSUs) are promises to deliver company shares to employees or executives only if the business meets specific performance targets and any time-based holding rules. Think of them as a bonus that converts into stock only after set goals are reached, so investors watch PRSUs for two reasons: they can dilute existing shares if paid out, and they signal how closely management’s pay is tied to company performance.

derivative security financial

"Exercise or conversion of derivative security"

A derivative security is a financial contract whose value comes from the price or performance of something else, such as a stock, bond, commodity, or market index. For investors it acts like an insurance policy or a wager: it can be used to protect against losses, lock in prices, or amplify gains and losses, so it can change a portfolio’s risk and potential return without owning the underlying asset directly.

contingent right financial

"Each restricted stock unit (RSU) represents the contingent right to receive one share"

Form 4 Insider Transactions: What Each Field Means →

05/05/2026 - 04:59 PM

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^*

Hellmann Elisabeth A

(Last)

(First)

(Middle)

C/O MASIMO CORPORATION

52 DISCOVERY

(Street)

IRVINE

CALIFORNIA

92618

(City)

(State)

(Zip)

UNITED STATES

(Country)

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)
	Chief Human Resources Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/21/2026

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

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

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

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	04/21/2026		M		335⁽¹⁾	A	$0	335	D
Common Stock	04/21/2026		F		121⁽²⁾	D	$178.43	214	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Restricted Stock Units	⁽³⁾	04/21/2026		M			335	⁽¹⁾	04/21/2035	Common Stock	335	$0	1,005	D

Explanation of Responses:

1. As previously reported, the reporting person was granted 1,340 restricted stock units (RSUs) on April 21, 2025 and will vest ratably over four years, 25% of which vested on April 21, 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 performance restricted stock units.

3. Each restricted stock unit (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, Attorney-In-Fact	05/05/2026
	** 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.
* Form 4: SEC 1474 (03-26)

Source: View Original Filing on SEC EDGAR

FAQ

What insider transactions did Masimo (MASI) disclose for Elisabeth A. Hellmann?

Masimo reported that Chief Human Resources Officer Elisabeth A. Hellmann had 335 restricted stock units vest into common shares, and 121 shares were withheld by the company to satisfy tax withholding obligations. These transactions reflect routine equity compensation events rather than open-market buying or selling.

How many Masimo (MASI) shares were withheld for taxes in this Form 4?

The company withheld 121 shares of Masimo common stock at a price of $178.43 per share to cover tax withholding obligations. This tax-withholding disposition is coded as an “F” transaction and is not an open-market sale by the executive.

What RSU grant for Masimo (MASI) vested for the CHRO in this filing?

The filing notes a grant of 1,340 restricted stock units on April 21, 2025, which vest ratably over four years. On April 21, 2026, 25% of this grant, or 335 RSUs, vested and converted into an equal number of Masimo common shares for the executive.

How many Masimo (MASI) shares and RSUs does Elisabeth Hellmann hold after the transactions?

After the reported transactions, Elisabeth A. Hellmann directly holds 214 shares of Masimo common stock and 1,005 restricted stock units. Each RSU represents the contingent right to receive one Masimo common share when the applicable vesting conditions are met in future periods.

Were the Masimo (MASI) Form 4 transactions open-market buys or sells?

No, the transactions were not open-market trades. They consisted of RSU vesting and conversion into 335 common shares, along with a tax-withholding disposition of 121 shares. These are compensation-related and administrative rather than discretionary market purchases or sales.