# EDGAR Filing Document

**Accession Number:** 0000937556
**File Stem:** 0001104659-26-027790
**Filing Date:** 2026-3
**Character Count:** 16755
**Document Hash:** 3e1a5a7fe25c0373882ba5d28d3d6f3e
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-26-027790.hdr.sgml**: 20260313

**ACCESSION NUMBER**: 0001104659-26-027790

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260311

**FILED AS OF DATE**: 20260313

**DATE AS OF CHANGE**: 20260313

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Koffey Quentin
- **CENTRAL INDEX KEY:** 0001984174

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-33642
- **FILM NUMBER:** 26753956

**MAIL ADDRESS:**
- **STREET 1:** POLITAN CAPITAL MANAGEMENT LP
- **STREET 2:** 106 WEST 56TH STREET, 10TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10019
**REPORTING-OWNER**: 

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

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

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-33642
- **FILM NUMBER:** 26753959

**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
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Politan Capital Management GP LLC
- **CENTRAL INDEX KEY:** 0001984176

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

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-33642
- **FILM NUMBER:** 26753958

**BUSINESS ADDRESS:**
- **STREET 1:** 106 WEST 56TH STREET, 10TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10019
- **BUSINESS PHONE:** 646-690-2830

**MAIL ADDRESS:**
- **STREET 1:** 106 WEST 56TH STREET, 10TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10019
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Politan Capital Partners GP LLC
- **CENTRAL INDEX KEY:** 0001984175

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

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-33642
- **FILM NUMBER:** 26753957

**BUSINESS ADDRESS:**
- **STREET 1:** 106 WEST 56TH STREET, 10TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10019
- **BUSINESS PHONE:** 646-690-2830

**MAIL ADDRESS:**
- **STREET 1:** 106 WEST 56TH STREET, 10TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10019
**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:** 0103

**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

[ ] 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>Politan Capital Management LP<br><sub>(Last) (First) (Middle)</sub><br>106 WEST 56TH STREET<br>10TH FLOOR<br><sub>(Street)</sub><br>NEW YORK, NY 10019<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2026-03-11 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [ ] 10% Owner<br>[ ] Officer (give title below) [X] Other (specify below)<br>_Director by deputization_ |
| **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>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Politan Capital Management GP LLC<br><sub>(Last) (First) (Middle)</sub><br>106 WEST 56TH STREET<br>10TH FLOOR<br><sub>(Street)</sub><br>NEW YORK, NY 10019<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2026-03-11 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [ ] 10% Owner<br>[ ] Officer (give title below) [X] Other (specify below)<br>_Director by deputization_ |
| **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>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Politan Capital Partners GP LLC<br><sub>(Last) (First) (Middle)</sub><br>106 WEST 56TH STREET<br>10TH FLOOR<br><sub>(Street)</sub><br>NEW YORK, NY 10019<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2026-03-11 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [ ] 10% Owner<br>[ ] Officer (give title below) [X] Other (specify below)<br>_Director by deputization_ |
| **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>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Koffey Quentin<br><sub>(Last) (First) (Middle)</sub><br>106 WEST 56TH STREET<br>10TH FLOOR<br><sub>(Street)</sub><br>NEW YORK, NY 10019<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2026-03-11 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [ ] 10% Owner<br>[ ] Officer (give title below) [X] Other (specify below)<br>_Director by deputization_ |
| **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>[ ] Form filed by One Reporting Person<br>[X] 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 |
|  |  |  |  |  |  |  |  |  |  |  |

---

## 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 |
| Forward Sale Contract (obligation to sell) | <sup>(1)(2)</sup> | 2026-03-11 |  | J<sup>(1)(2)</sup> |  | 142681<sup>(1)(2)</sup> |  | <sup>(1)(2)</sup> | <sup>(1)(2)</sup> | Common Stock | 142681 | <sup>(1)(2)</sup> | 142681 | I | See footnotes<sup>(3)(4)(5)(6)(7)</sup> |
| Forward Sale Contract (obligation to sell) | <sup>(8)(9)</sup> | 2026-03-12 |  | J<sup>(8)(9)</sup> |  | 130869<sup>(8)(9)</sup> |  | <sup>(8)(9)</sup> | <sup>(8)(9)</sup> | Common Stock | 130869 | <sup>(8)(9)</sup> | 130869 | I | See footnotes<sup>(3)(4)(5)(6)(7)</sup> |

---

### Footnotes:

(1) On March 11, 2026, Politan Capital Partners Master Fund LP, a Cayman Islands exempted limited partnership ("Politan Master Fund"), entered into a forward sale contract (the "March 11 Forward Contract") with a financial institution (the "Counterparty"). The March 11 Forward Contract obligates Politan Master Fund to deliver 142,681 common shares of MASI (the "March 11 Number of Shares") on the maturity date, August 12, 2026, subject to customary adjustments. In exchange, Politan Master Fund will receive an upfront payment of $24,802,095.85 on or around the trade date, which is based on a trade price of $175.48 per share. Politan Master Fund pledged the March 11 Number of Shares under the March 11 Forward Contract to secure its obligations under the transaction, and retained dividend and voting rights in such pledged shares.

(2) (continued from footnote 1) In addition, Politan Master Fund may request to increase the March 11 Number of Shares to be delivered by providing the Counterparty with notice (an "Additional Number of Shares Notice") and, if accepted, the details of the updated transaction will be made available by the Counterparty on a notice (an "Adjustment Notice"). The maturity date of the March 11 Forward Contract may be extended one month to September 12, 2026, at the election of Politan Master Fund. Upon maturity, if the March 11 Forward Contract is cash settled the cash settlement price payable by Politan Master Fund will be calculated on the basis of volume weighted average price per share at maturity. Alternatively, if the March 11 Forward Contract is physically settled, Politan Master Fund will deliver the March 11 Number of Shares (together with any additional number of shares listed in any applicable Adjustment Notice) reflecting the total March 11 Number of Shares sold to the Counterparty.

(3) In addition to Politan Capital Management LP, a Delaware limited partnership ("Politan"), this Form 4 is being filed jointly by Politan Capital Management GP LLC, a Delaware limited liability company ("Politan Management"), Politan Capital Partners GP LLC, a Delaware limited liability company ("Politan GP"), and Quentin Koffey, a citizen of the United States of America (together with Politan, Politan Management and Politan GP, the "Reporting Persons"), each of whom has the same business address as Politan and may be deemed to have a pecuniary interest in securities reported on this Form 4 (the "Subject Securities").

(4) Politan is the investment advisor to certain funds, including Politan Capital Partners LP, a Delaware limited partnership ("Politan LP"), Politan Capital Offshore Partners LP, a Cayman Islands exempted limited partnership ("Politan Offshore"), and Politan Master Fund (collectively with Politan Offshore and Politan LP, the "Politan Funds").

(5) Politan, as the investment advisor of the Politan Funds, may be deemed to be the beneficial owner of the Subject Securities for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934. As the general partner of Politan, Politan Management may be deemed to be the beneficial owner of the Subject Securities for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934. As the general partner of the Politan Funds, Politan GP may be deemed to be the beneficial owner of the Subject Securities for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934.

(6) By virtue of Mr. Koffey's position as managing partner and chief investment officer of Politan, and as the managing member of Politan Management and Politan GP, Mr. Koffey may be deemed to be the beneficial owner of the Subject Securities for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934. Each of the Reporting Persons disclaims any beneficial ownership of any of the Subject Securities, except to the extent of any pecuniary interest therein.

(7) Mr. Koffey is a member of the board of directors of the Issuer of the Subject Securities, and as a result, each of the other Reporting Persons may be directors by deputization for purposes of Section 16 of the Securities Exchange Act of 1934.

(8) On March 12, 2026, Politan Master Fund, entered into a forward sale contract (the "March 12 Forward Contract") with the Counterparty. The March 12 Forward Contract obligates Politan Master Fund to deliver 130,869 common shares of MASI (the "March 12 Number of Shares") on the maturity date, August 13, 2026, subject to customary adjustments. In exchange, Politan Master Fund will receive an upfront payment of $22,749,606 on or around the trade date, which is based on a trade price of $175.48 per share. Politan Master Fund pledged the March 12 Number of Shares under the March 12 Forward Contract to secure its obligations under the transaction, and retained dividend and voting rights in such pledged shares.

(9) (continued from footnote 8) In addition, Politan Master Fund may request to increase the March 12 Number of Shares to be delivered by providing the Counterparty with an Additional Number of Shares Notice, and, if accepted, the details of the updated transaction will be made available by the Counterparty on an Adjustment Notice. The maturity date of the March 12 Forward Contract may be extended one month to September 13, 2026, at the election of Politan Master Fund. Upon maturity, if the March 12 Forward Contract is cash settled the cash settlement price payable by Politan Master Fund will be calculated on the basis of volume weighted average price per share at maturity. Alternatively, if the March 12 Forward Contract is physically settled, Politan Master Fund will deliver the March 12 Number of Shares (together with any additional number of shares listed in any applicable Adjustment Notice) reflecting the total March 12 Number of Shares sold to the Counterparty.

**Signature:** Politan Capital Management LP By: Politan Capital Management GP LLC, its General Partner /s/ Quentin Koffey, Managing Member  
**Date:** 2026-03-13

**Signature:** Politan Capital Management GP LLC /s/ Quentin Koffey, Managing Member  
**Date:** 2026-03-13

**Signature:** Politan Capital Partners GP LLC /s/ Quentin Koffey, Managing Member  
**Date:** 2026-03-13

**Signature:** /s/ Quentin Koffey  
**Date:** 2026-03-13

### 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.**