Catherine M. Szyman - 10 Jun 2026 Form 4 Insider Report for MASIMO CORP (MASI)

Reporting relationship: Chief Executive Officer, Director
Issuer ticker: MASI
Reported as of: 10 Jun 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 12 Jun 2026, 16:30:12 UTC
Prior SEC filing: 16 Mar 2026
Source filing: View source filing
Reporting owner signature: /s/ Micah W. Young, Attorney-In-Fact

Key filing fact

Catherine M. Szyman filed Form 4 for MASIMO CORP (MASI) on 12 Jun 2026.

Key facts

This page summarizes Catherine M. Szyman's Form 4 filing for MASIMO CORP (MASI).
6 reported transactions and 5 derivative rows are listed below.
Accepted by SEC: 12 Jun 2026, 16:30.

Change

Previous filing in this sequence was filed on 16 Mar 2026.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001438538 Primary reporting owner

Szyman Catherine M.

Relationship: Chief Executive Officer, Director
Address: C/O MASIMO CORPORATION, 52 DISCOVERY, IRVINE
Signature: /s/ Micah W. Young, Attorney-In-Fact
Signature date: 12 Jun 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

MASI transaction

Common Stock

Disposed to Issuer

Transaction value
Shares: -7,605
Change %: -100%
Price: $180.00^*
Shares after: 0
Date: 10 Jun 2026
Ownership: Direct
Footnotes: F1, F2

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

MASI transaction Derivative

Restricted Stock Units

Disposed to Issuer

Transaction value
Shares: -22,283
Change %: -100%
Price
Shares after: 0
Date: 10 Jun 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 22,283
Exercise price
Footnotes: F1, F3, F4

MASI transaction Derivative

Restricted Stock Units

Disposed to Issuer

Transaction value
Shares: -6,306
Change %: -100%
Price
Shares after: 0
Date: 10 Jun 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 6,306
Exercise price
Footnotes: F1, F3, F5

MASI transaction Derivative

Restricted Stock Units

Disposed to Issuer

Transaction value
Shares: -39,904
Change %: -100%
Price
Shares after: 0
Date: 10 Jun 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 39,904
Exercise price
Footnotes: F1, F3, F6

MASI transaction Derivative

Non-Qualified Stock Option (Right to Buy)

Disposed to Issuer

Transaction value
Shares: -18,617
Change %: -100%
Price: $13.48^*
Shares after: 0
Date: 10 Jun 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 18,617
Exercise price: $166.52
Footnotes: F1, F7

MASI transaction Derivative

Performance-Based Restricted Stock Unit

Disposed to Issuer

Transaction value
Shares: -49,243
Change %: -100%
Price: $180.00^*
Shares after: 0
Date: 10 Jun 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 49,243
Exercise price
Footnotes: F1, F8, F9

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Section 16 status

Catherine M. Szyman is no longer subject to Section 16 filing requirements. Form 4 or Form 5 obligations may still apply in specific circumstances.

Explanation of responses 9 footnotes

Footnote F1

On June 10, 2026, pursuant to the Agreement and Plan of Merger, dated February 16, 2026, by and among Masimo Corporation (the "Issuer"), Danaher Corporation ("Parent"), and Mobius Merger Sub, Inc. ("Merger Sub"), Merger Sub merged with and into the Issuer, with the Issuer continuing as the surviving corporation and a wholly owned subsidiary of Parent (the "Merger").

Footnote F2

On June 10, 2026, at the effective time of the Merger, each share of the Issuer's common stock, par value $0.001 per share (the "Common Stock") issued and outstanding prior to the effective time of the Merger (other than certain excluded shares and dissenting shares) was canceled, extinguished and converted into the right to receive an amount in cash equal to $180.00 per share, without interest (the "Per Share Merger Consideration").

Footnote F3

On June 10, 2026, at the effective time of the Merger, each of the Issuer's restricted stock units ("RSUs") (other than certain RSUs held by the Issuer's non-employee directors) was assumed by Parent and converted into a number of RSUs of Parent equal to the product of the number of shares of Parent common stock equal to the number of shares of Common Stock underlying such RSU multiplied by the quotient of (a) the Per Share Merger Consideration, divided by (b) the volume-weighted average trading price per share of Parent's common stock for the ten trading day period ending on and including June 10, 2026 ($183.33).

Footnote F4

Represents the unvested portion of RSUs granted on February 12, 2025, which award of RSUs was to vest ratably over three years.

Footnote F5

Represents the unvested portion of RSUs granted on March 11, 2025, which award of RSUs was to vest ratably over four years.

Footnote F6

Represents the unvested portion of RSUs granted on March 6, 2026, which award of RSUs was to vest ratably over four years.

Footnote F7

On June 10, 2026, at the effective time of the Merger, each of the Issuer's stock options outstanding as of immediately prior to the effective time of the Merger, whether vested or unvested, were canceled and converted into the right to receive, for each share of Common Stock subject to such option, the excess, if any, of the Per Share Merger Consideration over the exercise price per share of such option, without interest and less any applicable tax withholding.

Footnote F8

On June 10, 2026, at the effective time of the Merger, each of the Issuer's performance-based restricted stock units ("PSUs") outstanding as of immediately prior to the effective time of the Merger, as determined at target performance, were canceled and converted into the right to receive $180.00 for each share of Common Stock underlying such award of PSUs, without interest and less any applicable tax withholding.

Footnote F9

Represents the PSUs granted on March 11, 2025, which represented the right to receive shares of Common Stock over a three year performance period, determined at target performance.