Thomas P. Gallagher - Aug 26, 2025 Form 4 Insider Report for MIAMI INTERNATIONAL HOLDINGS, INC. (MIAX)

Role: Chairman & CEO, Director
Signature: /s/Alessandra Maria Corona Henriques, Attorney-in-Fact
Stock symbol: MIAX
Transactions as of: Aug 26, 2025
Transactions value $: -$6,516,258
Form type: 4
Date filed: 8/28/2025, 04:33 PM
Previous filing: Aug 19, 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Gallagher Thomas P.	Chairman & CEO, Director	C/O MIAMI INTERNATIONAL HOLDINGS, INC, 7 ROSZEL ROAD, SUITE 1A, PRINCETON	/s/Alessandra Maria Corona Henriques, Attorney-in-Fact	2025-08-28	0002080477

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	MIAX	Common Stock	Tax liability	-$6.52M	-192K	-9.42%	$33.90	1.85M	Aug 26, 2025	By Gallagher Investments, LLC	F1, F2
holding	MIAX	Common Stock						588K	Aug 26, 2025	Direct	F3

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	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.
F2	Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC.
F3	Corrects previously reported holdings to reflect an additional 2,000 shares purchased on August 13, 2025, which are held jointly with his spouse with right of survival.