# EDGAR Filing Document

**Accession Number:** 0000937556
**File Stem:** 0000902664-26-001168
**Filing Date:** 2026-2
**Character Count:** 16195
**Document Hash:** 6dc2e081b5f89a9787c4f46f65a082a7
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000902664-26-001168.hdr.sgml**: 20260217

**ACCESSION NUMBER**: 0000902664-26-001168

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13D/A

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20260217

**DATE AS OF CHANGE**: 20260217

**SUBJECT COMPANY**: 

**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:** 0103

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-83497
- **FILM NUMBER:** 26645086

**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
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Politan Capital Management LP
- **CENTRAL INDEX KEY:** 0001885245

**ORGANIZATION NAME:**
- **EIN:** 871666292
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A

**BUSINESS ADDRESS:**
- **STREET 1:** C/O MCDERMOTT WILL & SCHULTE LLP
- **STREET 2:** 919 THIRD AVENUE
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10022
- **BUSINESS PHONE:** (646) 690-2838

**MAIL ADDRESS:**
- **STREET 1:** C/O MCDERMOTT WILL & SCHULTE LLP
- **STREET 2:** 919 THIRD AVENUE
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10022

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

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**(Amendment No. 16)**

**MASIMO CORP**

*(Name of Issuer)*

**Common Stock, par value $0.001 per share**

*(Title of Class of Securities)*

**574795100**

*(CUSIP Number)*

**Quentin Koffey**<br>Politan Capital Management LP<br>106 West 56th Street, 10th Floor<br>New York NY 10019<br>646-690-2830

*(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)*

**02/16/2026**

*(Date of Event Which Requires Filing of this Statement)*

| **CUSIP No.** | **574795100** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Politan Capital Management LP** | Name of reporting person<br>**Politan Capital Management LP** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**OO** | Source of funds (See Instructions)<br>**OO** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**4586630.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**4586630.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**4586630.00** | Aggregate amount beneficially owned by each reporting person<br>**4586630.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**6.2%** | Percent of class represented by amount in Row (11)<br>**6.2%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IA** | Type of Reporting Person (See Instructions)<br>**IA** | |

---

| **CUSIP No.** | **574795100** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Politan Capital Management GP LLC** | Name of reporting person<br>**Politan Capital Management GP LLC** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**OO** | Source of funds (See Instructions)<br>**OO** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**4586630.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**4586630.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**4586630.00** | Aggregate amount beneficially owned by each reporting person<br>**4586630.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**6.2%** | Percent of class represented by amount in Row (11)<br>**6.2%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IA** | Type of Reporting Person (See Instructions)<br>**IA** | |

---

| **CUSIP No.** | **574795100** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Politan Capital Partners GP LLC** | Name of reporting person<br>**Politan Capital Partners GP LLC** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**OO** | Source of funds (See Instructions)<br>**OO** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**4586630.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**4586630.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**4586630.00** | Aggregate amount beneficially owned by each reporting person<br>**4586630.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**6.2%** | Percent of class represented by amount in Row (11)<br>**6.2%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IA** | Type of Reporting Person (See Instructions)<br>**IA** | |

---

| **CUSIP No.** | **574795100** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Quentin Koffey** | Name of reporting person<br>**Quentin Koffey** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**OO** | Source of funds (See Instructions)<br>**OO** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**X1** | Citizenship or place of organization<br>**X1** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**4243.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**4586630.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**4243.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**4586630.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**4590873.00** | Aggregate amount beneficially owned by each reporting person<br>**4590873.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**6.2%** | Percent of class represented by amount in Row (11)<br>**6.2%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

**Comment for Reporting Person:** The amounts in rows 7, 9 and 11 include 4,243 restricted share units granted to Mr. Koffey in connection with his service as a director on the Board, 3,018 of which have vested as of the date hereof and 1,225 of which are scheduled to vest on the earlier of the first anniversary of the grant date or the date of the Issuer's 2026 annual meeting of stockholders.

**Item 1. Security and Issuer**

**(a) Title of Class of Securities:**
Common Stock, par value $0.001 per share

**(b) Name of Issuer:**
MASIMO CORP

**(c) Address of Issuer's Principal Executive Offices:**
52 Discovery, Irvine, CA, 92618

This Amendment No. 16 to Schedule 13D (this "Amendment No. 16") amends and supplements the Schedule 13D filed on August 16, 2022 (as amended and supplemented through the date of this Amendment No. 16, collectively, the "Schedule 13D") by the Reporting Persons, relating to the common stock, par value $0.001 per share, of Masimo Corporation, a Delaware corporation (the "Issuer"). Capitalized terms not defined in this Amendment No. 16 shall have the meaning ascribed to them in the Schedule 13D.

**Item 4. Purpose of Transaction**

Item 4 is hereby amended and supplemented as follows:

On February 16, 2026, the Issuer entered into an Agreement and Plan of Merger (the "Merger Agreement") with Danaher Corporation, a Delaware corporation ("Parent"), and Mobius Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Parent ("Merger Sub"), pursuant to which, among other things, Merger Sub will merge with and into the Issuer (the "Merger"), with the Issuer continuing as the surviving corporation and a wholly owned subsidiary of Parent.

On February 16, 2026, in connection with the execution of the Merger Agreement, Politan entered into a Voting and Support Agreement (the "Voting Agreement") with Parent, Merger Sub and the Issuer, pursuant to which and on the terms and subject to the conditions thereof, among other things, Politan has agreed to customary transfer restrictions and to vote its shares of Common Stock in favor of the adoption of the Merger Agreement and the approval of the Merger.

The foregoing summary of the Voting Agreement is not complete and is qualified in its entirety by reference to the full text of the Voting Agreement, a copy of which is included as Exhibit 99.18 to this Schedule 13D by reference to Exhibit 10.1 to the Issuer's Current Report on Form 8-K, filed with the SEC on February 17, 2026, and is incorporated by reference herein.

**Item 5. Interest in Securities of the Issuer**

**(a)**
Item 5(a) is hereby amended and restated in its entirety as follows:

See rows (11) and (13) of the cover pages to this Schedule 13D for the aggregate number of shares of Common Stock and percentages of the shares of Common Stock beneficially owned by each Reporting Person. The percentages used in this Schedule 13D are calculated based upon 74,218,782 shares of Common Stock outstanding as of February 13, 2026, as disclosed in the Merger Agreement, which was included as Exhibit 2.1 to the Issuer's Current Report on Form 8-K, filed with the SEC on February 17, 2026.

**(b)**
Item 5(b) is hereby amended and restated in its entirety as follows:

See rows (7) through (10) of the cover pages to this Schedule 13D for the number of shares of Common Stock as to which each Reporting Person has the sole or shared power to vote or direct the vote and sole or shared power to dispose or to direct the disposition.

**(c)**
Item 5(c) is hereby amended and restated in its entirety as follows:

No transactions in the shares of Common Stock have been effected by the Reporting Persons during the past sixty (60) days.

**Item 6. Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer.**

Item 6 is hereby amended and restated as follows:

The information provided or incorporated by reference in Item 4 is hereby incorporated by reference herein.

A certain portion of the shares of Common Stock beneficially owned by the Reporting Persons is held in one or more collateral accounts subject to a standard margin loan facility between Politan Master Fund and unaffiliated financial lender parties.

Except as set forth herein, the Reporting Persons have no contracts, arrangements, understandings or relationships (legal or otherwise) with respect to any securities of the Issuer, including any class of the Issuer's securities used as a reference security, in connection with any of the following: call options, put options, security-based swaps or any other derivative securities, transfer or voting of any of the securities, finder's fees, joint ventures, loan or option arrangements, guarantees of profits, division of profits or loss, or the giving or withholding of proxies.

### SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Politan Capital Management LP

**Signature:** /s/ Quentin Koffey

**Name/Title:** Quentin Koffey, Managing Member

**Date:** 02/17/2026

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Politan Capital Management GP LLC

**Signature:** /s/ Quentin Koffey

**Name/Title:** Quentin Koffey, Managing Member

**Date:** 02/17/2026

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Politan Capital Partners GP LLC

**Signature:** /s/ Quentin Koffey

**Name/Title:** Quentin Koffey, Managing Member

**Date:** 02/17/2026

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Quentin Koffey

**Signature:** /s/ Quentin Koffey

**Name/Title:** Quentin Koffey

**Date:** 02/17/2026