# EDGAR Filing Document

**Accession Number:** 0000937556
**File Stem:** 0001104659-26-073518
**Filing Date:** 2026-6
**Character Count:** 9003
**Document Hash:** aa146f80dcfe702a4455e2711ecc8f7b
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-26-073518.hdr.sgml**: 20260612

**ACCESSION NUMBER**: 0001104659-26-073518

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260610

**FILED AS OF DATE**: 20260612

**DATE AS OF CHANGE**: 20260612

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Hellmann Elisabeth A
- **CENTRAL INDEX KEY:** 0001870256

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-33642
- **FILM NUMBER:** 261087321

**MAIL ADDRESS:**
- **STREET 1:** C/O MASIMO CORPORATION
- **STREET 2:** 52 DISCOVERY
- **CITY:** IRVINE
- **STATE:** CA
- **ZIP:** 92618
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** MASIMO CORP
- **CENTRAL INDEX KEY:** 0000937556
- **STANDARD INDUSTRIAL CLASSIFICATION:** ELECTROMEDICAL & ELECTROTHERAPEUTIC APPARATUS [3845]
- **ORGANIZATION NAME:** 08 Industrial Applications and Services
- **EIN:** 330368882
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 0102

**BUSINESS ADDRESS:**
- **STREET 1:** 52 DISCOVERY
- **CITY:** IRVINE
- **STATE:** CA
- **ZIP:** 92618
- **BUSINESS PHONE:** 949-297-7000

**MAIL ADDRESS:**
- **STREET 1:** 52 DISCOVERY
- **CITY:** IRVINE
- **STATE:** CA
- **ZIP:** 92618

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

[x] 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**<sup>*</sup><br>Hellmann Elisabeth A<br><sub>(Last) (First) (Middle)</sub><br>C/O MASIMO CORPORATION<br>52 DISCOVERY<br><sub>(Street)</sub><br>IRVINE, CA 92618<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2026-06-10 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [ ] 10% Owner<br>[X] Officer (give title below) [ ] Other (specify below)<br>_Chief Human Resources Officer_ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>MASIMO CORP [ MASI ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[X] Form filed by One Reporting Person<br>[ ] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| Common Stock | 2026-06-10 |  | D |  | 214 | D | 180.00<sup>(1)(2)</sup> | 0 | D |  |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| Restricted Stock Units | <sup>(4)</sup> | 2026-06-10 |  | D |  |  | 1005 | <sup>(1)(3)(4)</sup> | <sup>(1)(3)(4)</sup> | Common Stock | 1005 | <sup>(3)</sup> | 0 | D |  |
| Restricted Stock Units | <sup>(5)</sup> | 2026-06-10 |  | D |  |  | 5985 | <sup>(1)(3)(5)</sup> | <sup>(1)(3)(5)</sup> | Common Stock | 5985 | <sup>(3)</sup> | 0 | D |  |
| Non-Qualified Stock Option (Right to Buy) | $149.24 | 2026-06-10 |  | D |  |  | 2873 | <sup>(1)(6)</sup> | <sup>(1)(6)</sup> | Common Stock | 2873 | 30.76<sup>(6)</sup> | 0 | D |  |
| Performance-Based Restricted Stock Unit | <sup>(8)</sup> | 2026-06-10 |  | D |  |  | 4020 | <sup>(1)(7)(8)</sup> | <sup>(1)(7)(8)</sup> | Common Stock | 4020 | 180.00<sup>(7)</sup> | 0 | D |  |

---

### Footnotes:

(1) 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").

(2) 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").

(3) 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 the (b) 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).

(4) Represents the unvested portion of RSUs granted on April 21, 2025, which award of RSUs was to vest ratably over four years.

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

(6) 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.

(7) 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.

(8) Represents the PSUs granted on April 21, 2025, which represented the right to receive shares of Common Stock over a three year performance period, determined at target performance.

**Signature:** /s/ Micah W. Young, Attorney-In-Fact  
**Date:** 2026-06-12

### Remarks:

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.**