MIAX (MIAX) EVP Comly surrenders shares for tax withholding, retains 843,844

Rhea-AI Filing Summary

MIAMI INTERNATIONAL HOLDINGS, INC. executive Barbara J. Comly reported a routine share disposition related to equity compensation. On this Form 4, 1,448 shares of common stock were surrendered to the company at $37.50 per share to cover tax withholding on vested restricted stock awards, which the footnote states does not represent a sale. After this tax-withholding transaction, she directly holds 843,844 shares of common stock.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Comly Barbara J.

Role EVP, GC & Corporate Secretary

Type	Security	Shares	Price	Value
Tax Withholding	Common Stock	1,448	$37.50	$54K

Holdings After Transaction: Common Stock — 843,844 shares (Direct)

Footnotes (1)

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Key Figures

Shares surrendered for tax withholding: 1,448 shares Valuation per share: $37.50 per share Shares held after transaction: 843,844 shares +1 more

4 metrics

Shares surrendered for tax withholding 1,448 shares Common Stock, transaction code F for tax liability

Valuation per share $37.50 per share Value used for tax-withholding disposition

Shares held after transaction 843,844 shares Direct ownership of Common Stock following Form 4 transaction

Transaction date 2026-03-30 Effective date of tax-withholding disposition

Key Terms

tax withholding, restricted stock awards, net settlement, Common Stock

4 terms

tax withholding financial

"to satisfy tax withholding and remittance obligations in connection with the net settlement"

Tax withholding is the practice of taking a portion of a payment—such as wages, dividends, or sale proceeds—before it reaches the recipient and sending that portion to the tax authority as an advance on the recipient’s eventual tax bill. For investors it matters because withholding reduces immediate cash received and affects after‑tax returns, estimated tax payments, and whether you may owe more or receive a refund when taxes are finally calculated, like having a small automatic savings set aside for your tax bill.

restricted stock awards financial

"in connection with the net settlement of restricted stock awards and does not represent a sale"

Restricted stock awards are company shares given to employees or executives that cannot be sold or transferred until certain conditions — like staying with the company for a set time or meeting performance targets — are met, like a gift that is locked in a safe until rules are satisfied. Investors care because these awards tie management’s pay to company performance, can increase the number of shares outstanding when they become tradable (dilution), and may signal expected future selling pressure or commitment to long-term growth.

net settlement financial

"in connection with the net settlement of restricted stock awards and does not represent a sale"

Common Stock financial

"security_title": "Common Stock""

Common stock represents ownership shares in a company, giving investors a stake in its success and a say in important decisions through voting rights. It is the most common type of stock traded on markets and can provide income through dividends, as well as potential for value growth. For investors, holding common stock means sharing in the company’s profits and risks.

Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

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

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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^*

Comly Barbara J.

(Last) (First) (Middle)

C/O MIAMI INTERNATIONAL HOLDINGS, INC.

7 ROSZEL ROAD, SUITE 1A

(Street)

PRINCETON NEW JERSEY 08540

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
MIAMI INTERNATIONAL HOLDINGS, INC. [ MIAX ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	EVP, GC & Corporate Secretary

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
03/30/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	03/30/2026		F		1,448(1)	D	$37.5	843,844	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Represents shares that have been surrendered to the Company to satisfy tax withholding and remittance obligations in connection with the net settlement of restricted stock awards and does not represent a sale by the reporting person.

Remarks:

	/s/Alessandra Maria Corona Henriques, Attorney-in-Fact	04/01/2026
	** Signature of Reporting Person	Date
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.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transaction did MIAX executive Barbara J. Comly report on this Form 4?

Barbara J. Comly reported surrendering 1,448 MIAX common shares to the company. The shares were used to satisfy tax withholding obligations from restricted stock awards and are not an open-market sale, according to the filing’s descriptive transaction code and footnote.

Was the MIAX Form 4 transaction by Barbara J. Comly a stock sale in the open market?

No, the Form 4 states the transaction was for tax withholding. The 1,448 shares were surrendered back to the company to cover tax obligations from restricted stock awards, and the footnote explicitly clarifies it does not represent a sale by the reporting person.

At what price were the MIAX shares valued for Barbara J. Comly’s tax-withholding disposition?

The 1,448 MIAX common shares surrendered for tax withholding were valued at $37.50 per share. This value reflects how the filing records the tax-withholding disposition associated with the net settlement of restricted stock awards for the executive.

How many MIAX shares does Barbara J. Comly hold after the reported Form 4 transaction?

After the tax-withholding disposition, Barbara J. Comly directly holds 843,844 MIAX common shares. This post-transaction figure in the Form 4 shows her continuing equity stake following the surrender of shares to satisfy tax-related obligations on restricted stock awards.

What does the tax-withholding transaction code F mean in the MIAX Form 4 for Barbara J. Comly?

Code F indicates shares delivered to pay an exercise price or tax liability. In this MIAX Form 4, it reflects shares surrendered to satisfy tax withholding and remittance obligations tied to restricted stock awards, not an open-market purchase or sale of common stock.