STOCK TITAN

Masimo (MASI) chair exercises 1,225 RSUs and receives 1,119-unit grant

Filing Impact
(Moderate)
Filing Sentiment
(Neutral)
Form Type
4

Rhea-AI Filing Summary

Masimo Corp director Michelle Brennan reported equity compensation activity. She exercised 1,225 restricted stock units into the same number of common shares, leaving her with 8,543 common shares held directly after the transactions.

She also received a new grant of 1,119 restricted stock units, each representing the contingent right to one common share upon vesting. According to the disclosures, these RSUs will vest in full on the earlier of the first anniversary of their grant date or the date of the next annual meeting of stockholders.

Positive

  • None.

Negative

  • None.
Insider Brennan Michelle
Role null
Type Security Shares Price Value
Exercise Restricted Stock Units 1,225 $0.00 --
Exercise Common Stock 1,225 $0.00 --
Grant/Award Restricted Stock Units 1,119 $178.71 $200K
Holdings After Transaction: Restricted Stock Units — 0 shares (Direct, null); Common Stock — 8,543 shares (Direct, null)
Footnotes (1)
  1. Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of the Issuer upon vesting of the RSU. These RSUs were granted on April 29, 2025 and will vest in full on the earlier of the first anniversary of the grant date or the date of the next annual meeting of stockholders following the date of grant. These RSUs were granted on April 23, 2026 and will vest in full on the earlier of the first anniversary of the grant date or the date of the next annual meeting of stockholders following the date of grant.
RSUs exercised 1,225 units Converted into 1,225 Masimo common shares on April 29, 2026
Shares held after transactions 8,543 shares Common stock directly owned following April 29, 2026 exercise
New RSU grant 1,119 units Restricted stock units granted April 23, 2026
RSU grant price reference $178.71 per unit Transaction price per share shown for April 23, 2026 RSU grant
Derivative exercises 1 exercise, 1,225 shares Aggregate derivative exercise activity in this Form 4
Restricted Stock Units financial
"These RSUs were granted on April 23, 2026 and will vest in full on the earlier of the first anniversary of the grant date or the date of the next annual meeting of stockholders"
Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.
contingent right financial
"Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock"
derivative security financial
"transaction_code_description": "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.
grant, award, or other acquisition financial
"transaction_code_description": "Grant, award, or other acquisition""
expiration date financial
"expiration_date": "2036-04-23T00:00:00.000Z""
The expiration date is the deadline after which a financial contract, such as an option or a futures agreement, is no longer valid or can be exercised. It matters to investors because it determines the timeframe during which they can take action or benefit from the contract, similar to how a coupon or a food item has a limited period of usefulness. Once the expiration date passes, the contract loses its value or ability to be used.
SEC Form 4
FORM 4UNITED 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*
Brennan Michelle

(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)
XDirector10% Owner
Officer (give title below)XOther (specify below)
Chairman of the Board
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
04/23/2026
6. Individual or Joint/Group Filing (Check Applicable Line)
XForm 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)
CodeVAmount(A) or (D)Price
Common Stock04/29/2026M1,225A$08,543D
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)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount or Number of Shares
Restricted Stock Units(1)04/29/2026M1,225 (2)04/29/2035Common Stock1,225$00D
Restricted Stock Units(1)04/23/2026A1,119 (3)04/23/2036Common Stock1,119$178.712,238D
Explanation of Responses:
1. Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of the Issuer upon vesting of the RSU.
2. These RSUs were granted on April 29, 2025 and will vest in full on the earlier of the first anniversary of the grant date or the date of the next annual meeting of stockholders following the date of grant.
3. These RSUs were granted on April 23, 2026 and will vest in full on the earlier of the first anniversary of the grant date or the date of the next annual meeting of stockholders following the date of grant.
Remarks:
/s/ Micah W. Young, Attorney-In-Fact05/05/2026
** Signature of Reporting PersonDate
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)

FAQ

What insider transactions did MASIMO CORP (MASI) director Michelle Brennan report?

Michelle Brennan reported exercising 1,225 restricted stock units into 1,225 shares of Masimo common stock and receiving a grant of 1,119 new restricted stock units as part of her equity compensation, with all holdings shown as direct ownership in the filing.

How many MASIMO CORP (MASI) shares does Michelle Brennan hold after these Form 4 transactions?

After exercising restricted stock units, Michelle Brennan holds 8,543 shares of Masimo common stock directly. This total reflects the newly acquired 1,225 shares from RSU conversion combined with her prior common stock holdings, as disclosed in the Form 4 data.

What restricted stock unit grants did Michelle Brennan receive from MASIMO CORP (MASI)?

She received a grant of 1,119 restricted stock units, each representing the right to one Masimo common share upon vesting. The filing also references earlier RSU grants, with terms defining when units convert into common stock based on time and annual meeting triggers.

When do Michelle Brennan’s MASIMO CORP (MASI) restricted stock units vest?

The filing states that the relevant restricted stock units vest in full on the earlier of the first anniversary of their grant date or the date of the next annual meeting of stockholders. Upon vesting, each unit entitles her to receive one share of common stock.

Did Michelle Brennan buy or sell MASIMO CORP (MASI) shares on the open market?

The Form 4 shows no open-market purchases or sales. Reported transactions are an RSU grant and the exercise or conversion of restricted stock units into common shares, which are compensation-related, not market trades at a chosen purchase or sale price.

What do MASIMO CORP (MASI) restricted stock units represent for Michelle Brennan?

Each restricted stock unit represents a contingent right to receive one share of Masimo common stock upon vesting. The units are part of her equity compensation and convert into common shares only when vesting conditions tied to time and stockholder meetings are satisfied.