# EDGAR Filing Document

**Accession Number:** 0000937556
**File Stem:** 0000902664-26-002759
**Filing Date:** 2026-6
**Character Count:** 14715
**Document Hash:** 461a745636cfea405c1e61a2e67a0490
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000902664-26-002759.hdr.sgml**: 20260611

**ACCESSION NUMBER**: 0000902664-26-002759

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

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20260611

**DATE AS OF CHANGE**: 20260611

**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:** 0102

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-83497
- **FILM NUMBER:** 261084779

**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. 17)**

**MASIMO CORP**

*(Name of Issuer)*

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

*(Title of Class of Securities)*

**—**

*(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)*

**06/10/2026**

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

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 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>[x] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[x] | |
| 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>**0.00** |
| 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>**0.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**0.00** | Aggregate amount beneficially owned by each reporting person<br>**0.00** | |
| 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>**0%** | Percent of class represented by amount in Row (11)<br>**0%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IA** | Type of Reporting Person (See Instructions)<br>**IA** | |

---

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 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>[x] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[x] | |
| 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>**0.00** |
| 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>**0.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**0.00** | Aggregate amount beneficially owned by each reporting person<br>**0.00** | |
| 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>**0%** | Percent of class represented by amount in Row (11)<br>**0%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IA** | Type of Reporting Person (See Instructions)<br>**IA** | |

---

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 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>[x] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[x] | |
| 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>**0.00** |
| 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>**0.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**0.00** | Aggregate amount beneficially owned by each reporting person<br>**0.00** | |
| 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>**0%** | Percent of class represented by amount in Row (11)<br>**0%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IA** | Type of Reporting Person (See Instructions)<br>**IA** | |

---

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 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>[x] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[x] | |
| 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>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**0.00** |
| 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>**0.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**0.00** | Aggregate amount beneficially owned by each reporting person<br>**0.00** | |
| 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>**0%** | Percent of class represented by amount in Row (11)<br>**0%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

**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. 17 to Schedule 13D (this "Amendment No. 17") amends and supplements the Schedule 13D filed on August 16, 2022 (as amended and supplemented through the date of this Amendment No. 17, 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. 17 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 June 10, 2026 (the "Closing Date"), the Merger was consummated pursuant to the Merger Agreement. At the effective time of the Merger (the "Effective Time"), Merger Sub merged with and into the Issuer, with the Issuer continuing as the surviving corporation and a wholly owned subsidiary of Parent.

At the Effective Time, each share of Common Stock issued and outstanding immediately prior to the Effective Time (other than shares excluded or treated as described in the Merger Agreement) was automatically cancelled, extinguished and converted into the right to receive an amount in cash equal to $180.00 per share, without interest and less any applicable withholding taxes (the "Per Share Merger Consideration"). Accordingly, the 4,590,873 shares of Common Stock beneficially owned by the Reporting Persons immediately prior to the Effective Time were converted into the right to receive the Per Share Merger Consideration. In addition, the 1,119 restricted share units held by Mr. Koffey, as a non-employee director of the Issuer, were cancelled and converted at the Effective Time into the right to receive an amount in cash equal to the Per Share Merger Consideration for each share of Common Stock underlying such restricted share units.

As a result of the Merger, the Reporting Persons ceased to beneficially own any shares of Common Stock.

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

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

As a result of the consummation of the Merger, as described in Item 4, each Reporting Person ceased to beneficially own any shares of Common Stock. See rows (11) and (13) of the cover pages to this Amendment No. 17, which reflect zero shares of Common Stock and 0.0% beneficially owned by each Reporting Person.

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

(b) See rows (7) through (10) of the cover pages to this Amendment No. 17. Each Reporting Person has no sole or shared power to vote or to direct the vote, and no sole or shared power to dispose or to direct the disposition, of any shares of Common Stock.

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

Except as set forth in Item 4, which is incorporated herein by reference, the Reporting Persons have not effected any transactions in the Common Stock 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.

### 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:** 06/11/2026

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:** 06/11/2026

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:** 06/11/2026

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:** 06/11/2026