Thomas P. Gallagher - Aug 15, 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 15, 2025
Transactions value $
$0
Form type
4
Date filed
8/19/2025, 04:06 PM
Previous filing
Aug 15, 2025
Next filing
Aug 28, 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 2025-08-19 0002080477

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction MIAX Common Stock Conversion of derivative security +500 +0.02% 2.04M Aug 15, 2025 By Gallagher Investments, LLC F1, F2
transaction MIAX Common Stock Conversion of derivative security +574K +4783.03% 586K Aug 15, 2025 Direct F3, F4
transaction MIAX Common Stock Conversion of derivative security +135K +7.11% 2.04M Aug 15, 2025 By Gallagher Investments, LLC F2, F5

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction MIAX Series B Preferred Stock Conversion of derivative security $0 -500 -100% $0.00 0 Aug 15, 2025 Common Stock 500 By Gallagher Investments, LLC F1, F2
transaction MIAX Nonvoting Common Stock Conversion of derivative security $0 -574K -100% $0.00 0 Aug 15, 2025 Common Stock 574K Direct F3
transaction MIAX Nonvoting Common Stock Conversion of derivative security $0 -135K -100% $0.00 0 Aug 15, 2025 Common Stock 135K By Gallagher Investments, LLC F2, F5
transaction MIAX Incentive Stock Option (Right to Buy) Options Exercise $0 -25K -100% $0.00 0 Aug 15, 2025 Nonvoting Common Stock 25K $12.00 Direct F6, F7
transaction MIAX Incentive Stock Option (Right to Buy) Options Exercise $0 +25K $0.00 25K Aug 15, 2025 Common Stock 25K $12.00 Direct F6, F7
transaction MIAX Incentive Stock Option (Right to Buy) Options Exercise $0 -16.7K -100% $0.00 0 Aug 15, 2025 Nonvoting Common Stock 16.7K $12.00 Direct F6, F7
transaction MIAX Incentive Stock Option (Right to Buy) Options Exercise $0 +16.7K $0.00 16.7K Aug 15, 2025 Common Stock 16.7K $12.00 Direct F6, F7
transaction MIAX Incentive Stock Option (Right to Buy) Options Exercise $0 -8.33K -100% $0.00 0 Aug 15, 2025 Nonvoting Common Stock 8.33K $12.00 Direct F6, F7
transaction MIAX Incentive Stock Option (Right to Buy) Options Exercise $0 +8.33K $0.00 8.33K Aug 15, 2025 Common Stock 8.33K $12.00 Direct F6, F7
transaction MIAX Incentive Stock Option (Right to Buy) Options Exercise $0 -13.1K -100% $0.00 0 Aug 15, 2025 Nonvoting Common Stock 13.1K $15.22 Direct F6, F7
transaction MIAX Incentive Stock Option (Right to Buy) Options Exercise $0 +13.1K $0.00 13.1K Aug 15, 2025 Common Stock 13.1K $15.22 Direct F6, F7
transaction MIAX Nonqualified Stock Option (Right to Buy) Options Exercise $0 -350K -100% $0.00 0 Aug 15, 2025 Nonvoting Common Stock 350K $12.00 By Gallagher Investments, LLC F2, F6, F7
transaction MIAX Nonqualified Stock Option (Right to Buy) Options Exercise $0 +350K $0.00 350K Aug 15, 2025 Common Stock 350K $12.00 By Gallagher Investments, LLC F2, F6, F7
transaction MIAX Nonqualified Stock Option (Right to Buy) Options Exercise $0 -283K -100% $0.00 0 Aug 15, 2025 Nonvoting Common Stock 283K $12.00 By Gallagher Investments, LLC F2, F6, F7
transaction MIAX Nonqualified Stock Option (Right to Buy) Options Exercise $0 +283K $0.00 283K Aug 15, 2025 Common Stock 283K $12.00 By Gallagher Investments, LLC F2, F6, F7
transaction MIAX Nonqualified Stock Option (Right to Buy) Options Exercise $0 -242K -100% $0.00 0 Aug 15, 2025 Nonvoting Common Stock 242K $12.00 By Gallagher Investments, LLC F2, F6, F7
transaction MIAX Nonqualified Stock Option (Right to Buy) Options Exercise $0 +242K $0.00 242K Aug 15, 2025 Common Stock 242K $12.00 By Gallagher Investments, LLC F2, F6, F7
transaction MIAX Nonqualified Stock Option (Right to Buy) Options Exercise $0 -287K -100% $0.00 0 Aug 15, 2025 Nonvoting Common Stock 287K $15.22 By Gallagher Investments, LLC F2, F6, F7
transaction MIAX Nonqualified Stock Option (Right to Buy) Options Exercise $0 +287K $0.00 287K Aug 15, 2025 Common Stock 287K $15.22 By Gallagher Investments, LLC F2, F6, F7
transaction MIAX Nonqualified Stock Option (Right to Buy) Options Exercise $0 -375K -100% $0.00 0 Aug 15, 2025 Nonvoting Common Stock 375K $16.14 By Gallagher Investments, LLC F2, F6, F7
transaction MIAX Nonqualified Stock Option (Right to Buy) Options Exercise $0 +375K $0.00 375K Aug 15, 2025 Common Stock 375K $16.14 By Gallagher Investments, LLC F2, F6, F7
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 Represents 500 shares of Series B Preferred Stock that have been converted into shares of Common Stock on a one-for-one basis upon the closing of the Company's initial public offering ("IPO") and which have no expiration date.
F2 Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC
F3 Represents 573,963 shares of Nonvoting Common Stock that have been converted into shares of Common Stock on a one-for-one basis upon the closing of the Company's IPO and which have no expiration date.
F4 Includes 12,000 shares of common stock jointly with his spouse with right of survival
F5 Represents 135,395 shares of Nonvoting Common Stock that have been converted into shares of Common Stock on a one-for-one basis upon the closing of the Company's IPO and which have no expiration date.
F6 The options were granted initially as the right to buy Nonvoting Common Stock. On the closing date of the IPO, these converted to the right to buy Common Stock instead of Nonvoting Common Stock, for the same price and under the same conditions.
F7 The options are fully vested.