Thomas P. Gallagher - 16 Jun 2026 Form 4 Insider Report for MIAMI INTERNATIONAL HOLDINGS, INC. (MIAX)

Reporting relationship: Chairman & CEO, Director
Issuer ticker: MIAX
Reported as of: 16 Jun 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 18 Jun 2026, 16:13:45 UTC
Prior SEC filing: 04 Jun 2026
Next SEC filing: 07 Jul 2026
Source filing: View source filing
Reporting owner signature: /s/Alessandra Maria Corona Henriques, Attorney-in-Fact

Key filing fact

Thomas P. Gallagher filed Form 4 for MIAMI INTERNATIONAL HOLDINGS, INC. (MIAX) on 18 Jun 2026.

Key facts

This page summarizes Thomas P. Gallagher's Form 4 filing for MIAMI INTERNATIONAL HOLDINGS, INC. (MIAX).
3 reported transactions and 2 derivative rows are listed below.
Accepted by SEC: 18 Jun 2026, 16:13.

Change

Previous filing in this sequence was filed on 04 Jun 2026.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0002080477 Primary reporting owner

Gallagher Thomas P.

Relationship: Chairman & CEO, Director
Address: C/O MIAMI INTERNATIONAL HOLDINGS, INC, 7 ROSZEL ROAD, SUITE 1A, PRINCETON
Signature: /s/Alessandra Maria Corona Henriques, Attorney-in-Fact
Signature date: 18 Jun 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

MIAX transaction

Common Stock

Award

Transaction value
Shares: +232,977
Change %: +46%
Price: $0.000000^*
Shares after: 743,939
Date: 16 Jun 2026
Ownership: Direct
Footnotes: F1

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

MIAX transaction Derivative

Incentive Stock Option (Right to Buy)

Award

Transaction value
Shares: +2,485
Change %
Price: $0.000000^*
Shares after: 2,485
Date: 16 Jun 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 2,485
Exercise price: $40.24
Footnotes: F2

MIAX transaction Derivative

Nonqualified Stock Option (Right to Buy)

Award

Transaction value
Shares: +237,175
Change %
Price: $0.000000^*
Shares after: 237,175
Date: 16 Jun 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 237,175
Exercise price: $40.24
Footnotes: F3

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 3 footnotes

Footnote F1

The amount represents restricted stock units ("RSUs") that vest as to 77,659 on June 16, 2027, 77,659 on June 16, 2028 and the remaining 77,659 on June 16, 2029, subject to the Reporting Person's continued service to the Issuer or its subsidiaries through the applicable vesting date.

Footnote F2

829 of the shares subject to this option will vest on June 16, 2027, 828 of the shares subject to this option will vest on June 16, 2028 and the remaining 828 of the shares subject to this option will vest on June 16, 2029, subject to the Reporting Person's continued service to the Issuer or its subsidiaries through the applicable vesting date.

Footnote F3

79,059 of the shares subject to this option will vest on June 16, 2027, 79,058 of the shares subject to this option will vest on June 16, 2028 and the remaining 79,058 of the shares subject to this option will vest on June 16, 2029, subject to the Reporting Person's continued service to the Issuer or its subsidiaries through the applicable vesting date.