[Form 4] Miami International Holdings, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Miami International Holdings insider Shelly Brown reported a change in beneficial ownership on Form 4. The filing shows that on 08/26/2025 Ms. Brown had 11,047 shares of common stock surrendered to the company to satisfy tax withholding obligations related to the net settlement of restricted stock awards; the filing notes this was not a sale. Following the transaction her beneficial ownership is reported as 327,982 shares. The Form 4 was signed by an attorney-in-fact on 08/28/2025 and discloses Ms. Brown's role as EVP, Strategic Planning & BD.

Insights

Financial Analyst

TL;DR: Insider surrendered shares for tax withholding, not an open-market sale; ownership modestly reduced to 327,982 shares.

The reported disposition of 11,047 shares reflects a tax-withholding event tied to the net settlement of restricted stock awards rather than a market sale, which generally reduces near-term signaling risk to investors. The transaction was executed at an indicated price of $33.90 per share for withholding purposes, though the form clarifies this represents share surrender to cover taxes. For valuation models this is a non-cash compensation settlement and does not imply incremental supply pressure from an intentional divestiture by the executive.

Corporate Governance Expert

TL;DR: Routine insider tax withholding disclosed; no governance red flags apparent from this Form 4.

The Form 4 discloses a standard administrative action where restricted stock awards are net-settled to satisfy tax obligations. The reporting person is an executive officer (EVP, Strategic Planning & BD), and the disclosure was signed via attorney-in-fact, which is common practice. There are no indications of unusual timing, derivative exercises, or sales that might raise governance or insider-trading concerns based on the information provided.

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
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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^*

Brown Shelly

(Last) (First) (Middle)

C/O MIAMI INTERNATIONAL HOLDINGS, INC.

7 ROSZEL ROAD, SUITE 1A

(Street)

PRINCETON NJ 08540

(City) (State) (Zip)

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, Strat. Planning & BD

3. Date of Earliest Transaction (Month/Day/Year)
08/26/2025

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

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

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

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	08/26/2025		F		11,047(1)	D	$33.9	327,982	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	08/28/2025
	** 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.

FAQ

What did Shelly Brown report on the MIAX Form 4?

She reported the surrender of 11,047 shares on 08/26/2025 to satisfy tax withholding related to restricted stock awards; this was not a sale.

How many MIAX shares does Shelly Brown own after the transaction?

She beneficially owns 327,982 shares following the reported transaction.

Was the transaction an open-market sale reported on the Form 4?

No. The filing states the shares were surrendered to cover tax withholding in connection with net settlement of restricted stock awards.

What price is shown on the Form 4 for the surrendered shares?

The form lists $33.90 per share as the price associated with the reported disposition for withholding purposes.

When was the transaction and when was the Form 4 signed?

The transaction date is 08/26/2025 and the Form 4 was signed by an attorney-in-fact on 08/28/2025.