Miami International (MIAX) CEO reports bona fide gift of 2,000 shares

Rhea-AI Filing Summary

Miami International Holdings, Inc. chairman and CEO reported a transfer of shares to a family member. On 12/23/2025, he made a bona fide gift of 2,000 shares of common stock to his son. The shares given are subject to a lock-up agreement that he entered into on December 11, 2025, and the son has agreed to be bound by that agreement.

After this gift, he beneficially owns 585,963 shares of Miami International Holdings common stock. This total includes 12,000 shares held jointly with his spouse with right of survival. The transaction is reported as a gift, so no price is associated with the transfer.

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

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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^*

Gallagher Thomas P.

(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)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chairman & CEO

3. Date of Earliest Transaction (Month/Day/Year)
12/23/2025

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	12/23/2025		G		2,000(1)	D	(2)	585,963(3)	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. Bona fide gift by Reporting Person of 2,000 shares of common stock to his son. The shares are subject to a lockup agreement entered into by the Reporting Person on December 11, 2025 (the "Lock-up Agreement"). The transferee has agreed to be bound by the terms of the Lock-up Agreement.

2. Price is not applicable to acquisitions or dispositions resulting from bona fide gifts.

3. Includes 12,000 shares of common stock, which are held jointly with the Reporting Person's spouse with right of survival.

Remarks:

	/s/ Barbara J. Comly, Attorney-in-fact	12/29/2025
	** 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 insider transaction did MIAX report in this Form 4?

The chairman and CEO of Miami International Holdings, Inc. (MIAX) reported a bona fide gift of 2,000 shares of common stock to his son on 12/23/2025.

Was the MIAX CEO’s 2,000-share transfer a sale or a gift?

The transaction is described as a bona fide gift of 2,000 shares of Miami International Holdings common stock to the reporting person’s son.

How many MIAX shares does the reporting person own after the gift?

Following the reported gift, the reporting person beneficially owns 585,963 shares of Miami International Holdings common stock.

Are any of the MIAX CEO’s shares held jointly with a spouse?

Yes. The reported holdings include 12,000 shares of common stock that are held jointly with the reporting person’s spouse with right of survival.

Is the 2,000-share MIAX gift subject to a lock-up agreement?

Yes. The 2,000 gifted shares are subject to a lock-up agreement the reporting person entered into on December 11, 2025, and the son has agreed to be bound by its terms.

Does the MIAX Form 4 transaction have an associated price?

No transaction price is listed because, as noted, price is not applicable to acquisitions or dispositions resulting from bona fide gifts.