Joe Kiani holds 3.66M shares of Masimo (NASDAQ: MASI), cites disputed awards

Rhea-AI Filing Summary

Joe Kiani reports beneficial ownership of 3,657,039 shares of Masimo Corporation common stock, representing 6.5% of the class. The total percent calculation uses 52,365,808 shares outstanding as of April 4, 2026. The reported position includes a mix of directly held shares, trusts, and multiple equity awards that the reporting person states are subject to dispute with Masimo, including 368,252 Exercised Options, 2,700,000 RSU Award shares, 158,450 Accelerated Options, 198,225 PSUs, and 85,255 Vested Options. The filing explains the issuer declined to process certain exercises and that the company has filed claims in the Delaware Court of Chancery; the reporting person includes contested awards in his beneficial ownership figures for transparency.

Insights

Corporate Governance Expert

Contested equity awards drive Kiani's 6.5% stake and active litigation with Masimo.

The filing lists 3,657,039 shares and explicitly includes awards the reporting person says were not issued due to a dispute. The percent uses April 4, 2026 outstanding shares of 52,365,808.

Governance implications hinge on the Delaware Court of Chancery claims; resolution of those claims will determine whether the contested awards convert to issued shares and change ownership math. Subsequent filings and court documents will clarify timing and final holdings.

Key Figures

Beneficial ownership: 3,657,039 shares Percent of class: 6.5% Shares outstanding: 52,365,808 shares +5 more

8 metrics

Beneficial ownership 3,657,039 shares reported amount beneficially owned

Percent of class 6.5% calculated using shares outstanding as of <date>April 4, 2026</date>

Shares outstanding 52,365,808 shares outstanding as of <date>April 4, 2026</date>

RSU Award included 2,700,000 shares RSU Award the reporting person says should have been issued

Exercised Options included 368,252 shares exercise notices submitted January 17, 2025 but not processed by issuer

Accelerated Options included 158,450 shares alleged to have vested as of October 24, 2024

PSUs included 198,225 shares performance RSUs at target, alleged to have accelerated October 24, 2024

Vested Options included 85,255 shares vested options as of October 24, 2024 that issuer asserts were cancelled

Key Terms

RSU Award, Exercised Options, Qualifying Termination, PSUs

4 terms

RSU Award financial

"the RSU Award that is subject to a dispute between the Issuer"

Exercised Options financial

"completed notices of exercise and shares...for the exercise of an aggregate of 368,252 shares"

Qualifying Termination regulatory

"upon a Qualifying Termination (as defined in the Employment Agreement)"

PSUs financial

"performance restricted stock unit awards with respect to an aggregate target number"

PSUs are company shares promised to employees or executives that only become actual stock if the business hits specific performance targets over a set period. For investors, PSUs matter because they link pay to measurable outcomes — similar to a conditional bonus that converts into ownership — which can influence management decisions, dilution of shares, and signals about confidence in future results.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 21)

Masimo Corporation

(Name of Issuer)

Common Stock, $0.0001 par value

(Title of Class of Securities)

574795100

(CUSIP Number)

03/31/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 574795100

1

Names of Reporting Persons

Joe Kiani

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 3,657,039.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 3,657,039.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

3,657,039.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

6.5 %

12

Type of Reporting Person (See Instructions)

IN

Comment for Type of Reporting Person: (1) Aggregate amount beneficially owned is comprised of (a) 5,000 shares of the Issuer's common stock held in the name of the Reporting Person, (b) 141,856 shares of the Issuer's common stock held in one trust for which the Reporting Person is the sole trustee, (c) 1 share of the Issuer's common stock held by a limited liability company that is owned by three trusts for which the Reporting Person is not the trustee, (d) 368,252 shares of the Issuer's common stock subject to the Exercised Options (as defined in Footnote (1) to Item 4(a) below) that are subject to a dispute between the Issuer and the Reporting Person as described in Footnote (1) to Item 4(a) below, (e) 2,700,000 shares of the Issuer's common stock that are subject to the RSU Award (as defined in Footnote (2) to Item 4(a) below) that is subject to a dispute between the Issuer and the Reporting Person as further described in Footnote (2) to Item 4(a) below, (f) 158,450 shares of the Issuer's common stock subject to the Accelerated Options (as defined in Footnote (3) to Item 4(a) below) that are subject to a dispute between the Issuer and the Reporting Person as described in Footnote (3) to Item 4(a) below, (g) 198,225 shares of the Issuer's common stock subject to the PSUs (as defined in Footnote (4) to Item 4(a) below) that are subject to a dispute between the Issuer and the Reporting Person as described in Footnote (4) to Item 4(a) below, and (h) 85,255 shares of the Issuer's common stock subject to the Vested Options (as defined in Footnote (5) to Item 4 (a) below) that are subject to a dispute between the Issuer and the Reporting Person as described in Footnote (5) to Item 4(a) below. (2) Percent of class was calculated based on: (a) 52,365,808 shares of the Issuer's common stock outstanding as of April 4, 2026 (as reported in the Issuer's Quarterly Report on Form 10-Q for the quarterly period ended April 4, 2026 filed with the Securities and Exchange Commission on May 5, 2026), (b) 368,252 shares of the Issuer's common stock issuable upon exercise of the Exercised Options that have not yet been issued by the Issuer to the Reporting Person, (c) 2,700,000 shares of the Issuer's common stock issuable underlying the RSU Award that have not yet been issued by the Issuer to the Reporting Person, (d) 158,450 shares of the Issuer's common stock issuable upon exercise of the Accelerated Options that should have been deemed vested in full on October 24, 2024, (e) 198,225 shares of the Issuer's common stock subject to the PSUs that should have been accelerated and issued by the Issuer to the Reporting Person on October 24, 2024, and (f) 85,255 shares of the Issuer's common stock subject to the Vested Options.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Masimo Corporation
(b)	Address of issuer's principal executive offices: 52 Discovery, Irvine, CA 92618
Item 2.
(a)	Name of person filing: Joe Kiani
(b)	Address or principal business office or, if none, residence: 121 Theory, Irvine, CA 92617
(c)	Citizenship: United States
(d)	Title of class of securities: Common Stock, $0.0001 par value
(e)	CUSIP No.: 574795100
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 3,657,039 shares of the Issuer's common stock, which is comprised of (a) 5,000 shares of the Issuer' held in the name of the Reporting Person, (b) 141,856 shares held in one trust for which the Reporting Person is the sole trustee, (c) 1 share held by a limited liability company that is owned by three trusts for which the Reporting Person is not the trustee, (d) 368,252 shares subject to the Exercised Options (as defined in Footnote (1) below) that are subject to a dispute between the Issuer and the Reporting Person as described in Footnote (1) below, (e) 2,700,000 shares that are subject to the RSU Award (as defined in Footnote (2) below) that is subject to a dispute between the Issuer and the Reporting Person as further described in Footnote (2) below, (f) 158,450 shares subject to the Accelerated Options (as defined in Footnote (3) below) that are subject to a dispute between the Issuer and the Reporting Person as described in Footnote (3) below, (g) 198,225 shares subject to the PSUs (as defined in Footnote (4) below) that are subject to a dispute between the Issuer and the Reporting Person as described in Footnote (4) below, and (h) 85,255 shares subject to the Vested Options (as defined in Footnote (5) below) that are subject to a dispute between the Issuer and the Reporting Person as described in Footnote (5) below. Footnotes: (1) On January 17, 2025, the Reporting Person provided the Issuer with completed notices of exercise and shares of the Issuer's common stock sufficient to satisfy the payment of the aggregate cash exercise price for the exercise of an aggregate of 368,252 shares of the Issuer's common stock (the "Exercised Options"). The Issuer declined to process the Reporting Person's exercise notices, alleging that the Reporting Person had been terminated with "cause" and that the Exercised Options had been cancelled and could not be exercised by the Reporting Person. The Reporting Person disagrees with the characterization that the Reporting Person's employment was terminated for "cause" or that the Exercised Options were cancelled or could not be exercised. The Reporting Person believes that the exercise notices for the Exercised Options should have been processed and that the Reporting Person should have been issued 368,252 shares of the Issuer's common stock upon exercise of the Exercised Options on January 17, 2025. Therefore, the Reporting Person has included the 368,252 shares of the Issuer's common stock subject to the Exercised Options as beneficially owned in this Schedule 13G/A even though the shares have not yet been issued to the Reporting Person. (2) In November 2015, the Issuer entered into an Amended and Restated Employment Agreement (the "Employment Agreement") with the Reporting Person, which provided, among other things, that upon a Qualifying Termination (as defined in the Employment Agreement), the Issuer would be obligated to issue the Reporting Person 2,700,000 shares of the Issuer's common stock pursuant to the terms of an RSU award agreement between the Issuer and the Reporting Person (the "RSU Award"). The Reporting Person's position is that a Qualifying Termination occurred pursuant to the Employment Agreement and that the Reporting Person should have been issued the 2,700,000 shares of the Issuer's common stock pursuant to the terms of the Employment Agreement and the RSU Award; however, the Issuer has not yet issued such shares to the Reporting Person and has filed claims against the Reporting Person in the Court of Chancery of the State of Delaware, seeking judicial declarations that, among other things, the Reporting Person is not entitled to receive the shares subject to the RSU Award. As the Reporting Person believes that the Issuer should have issued the 2,700,000 shares of the Issuer's common stock subject to the RSU Award to the Reporting Person, the Reporting Person has included the 2,700,000 shares of the Issuer's common stock as beneficially owned in this Schedule 13G/A even though the shares have not yet been issued to the Reporting Person. (3) The Employment Agreement also provided that all of the Reporting Person's stock options and other equity awards would vest, effective as of immediately prior to a Qualifying Termination. As of October 24, 2024, the last day of the Reporting Person's employment by the Issuer, the Reporting Person held unvested options to purchase an aggregate of 158,450 shares of the Issuer's common stock (the "Accelerated Options"). As noted above, the Reporting Person's position is that a Qualifying Termination occurred pursuant to the Employment Agreement and that the Issuer should have accelerated the vesting for the Accelerated Options in accordance with the Employment Agreement. Moreover, the Reporting Person's position is that the Employment Agreement provides that the Accelerated Options remain outstanding through their respective dates of expiration, which is ten years after the applicable grant date. Therefore, the Reporting Person has included 158,450 shares of the Issuer's common stock as beneficially owned in this Schedule 13G/A even though the Issuer did not accelerate the vesting for the Accelerated Options or make them available for exercise by the Reporting Person. In including the Accelerated Options in this Schedule 13G/A, the Reporting Person neither asserts nor denies beneficial ownership of the shares of Common Stock underlying the Accelerated Options but has included them herein for transparency. (4) As noted above, the Employment Agreement provided that all of the Reporting Person's stock options and other equity awards would vest, effective as of immediately prior to a Qualifying Termination. As of October 24, 2024, the last day of the Reporting Person's employment by the Issuer, the Reporting Person held performance restricted stock unit awards with respect to an aggregate target number of shares of the Issuer's common stock equal to 198,225 shares of the Issuer's common stock (the "PSUs"). As noted above, the Reporting Person's position is that a Qualifying Termination occurred pursuant to the Employment Agreement and that the Issuer should have accelerated the vesting for the PSUs at target in accordance with the Employment Agreement. Therefore, the Reporting Person has included 198,225 shares of the Issuer's common stock as beneficially owned in this Schedule 13G/A even though the Issuer did not accelerate the vesting for the PSUs or issue the target number of shares with respect to the PSUs on October 24, 2024. (5) As of October 24, 2024, the last day of the Reporting Person's employment by the Issuer, the Reporting Person held vested options to purchase an aggregate of 85,255 shares of the Issuer's common stock that were not among the Exercised Options or subsequently exercised by the Reporting Person (such options, the "Vested Options"). As noted above, the Issuer has alleged that the Reporting Person had been terminated with "cause" and that the Vested Options have been cancelled and cannot be exercised by the Reporting Person. However, the Reporting Person's position is that the Employment Agreement provides that the Vested Options remain outstanding through their respective dates of expiration, which is ten years after the applicable grant date. Therefore, the Reporting Person has included 85,255 shares of the Issuer's common stock as beneficially owned in this Schedule 13G/A even though the Issuer has asserted that the Vested Options have been cancelled. In including the Vested Options in this Schedule 13G/A, the Reporting Person neither asserts nor denies beneficial ownership of the shares of Common Stock underlying such options but has included them herein for transparency.
(b)	Percent of class: 6.5%; calculated based on: (a) 52,365,808 shares of the Issuer's common stock outstanding as of April 4, 2026 (as reported in the Issuer's Quarterly Report on Form 10-Q for the quarterly period ended April 4, 2026 filed with the Securities and Exchange Commission on May 5, 2026), (b) 368,252 shares of the Issuer's common stock issuable upon exercise of the Exercised Options that have not yet been issued by the Issuer to the Reporting Person, (c) 2,700,000 shares of the Issuer's common stock issuable underlying the RSU Award that have not yet been issued by the Issuer to the Reporting Person, (d) 158,450 shares of the Issuer's common stock issuable upon exercise of the Accelerated Options that should have been deemed vested in full on October 24, 2024, (e) 198,225 shares of the Issuer's common stock subject to the PSUs that should have been accelerated and issued by the Issuer to the Reporting Person on October 24, 2024, and (f) 85,255 shares of the Issuer's common stock subject to the Vested Options.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 3,657,039
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 3,657,039
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. The Reporting Person's spouse is entitled to receive dividends and sale proceeds.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.	Certifications:
	Not Applicable

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.

Joe Kiani

Signature:	/s/ Joe Kiani
Name/Title:	Individual
Date:	05/14/2026

Exhibit Information

N/A

FAQ

What stake in Masimo (MASI) does Joe Kiani report?

Direct answer: Joe Kiani reports beneficial ownership of 3,657,039 shares (6.5%). Context: That percentage is calculated using 52,365,808 shares outstanding as of April 4, 2026 and includes contested equity awards the filer believes should be issued.

Which contested awards are included in Kiani's ownership filing for MASI?

Direct answer: The filing includes 368,252 Exercised Options, 2,700,000 RSU Award shares, 158,450 Accelerated Options, 198,225 PSUs, and 85,255 Vested Options. Context: The reporting person states these awards are disputed and not yet issued by the company.

Does the filing reference litigation related to Kiani's equity awards at MASI?

Direct answer: Yes. The company has filed claims in the Delaware Court of Chancery seeking declarations about entitlement to awards. Context: The reporting person includes contested shares in his count while the dispute proceeds.

What outstanding share count does the MASI filing use to calculate percentage ownership?

Direct answer: The percent of class is calculated using 52,365,808 shares outstanding as of April 4, 2026. Context: That figure is cited from Masimo's Form 10-Q for the period ended April 4, 2026.

Are all shares included in Kiani's filing already issued?

Direct answer: No. Several included amounts represent awards the filer says should be issued but that the issuer has not issued. Context: The filing distinguishes between shares held, shares issuable on exercise, and awards the reporting person alleges were not processed.