MIAMI International Holdings (MIAX) EVP exercises 33,332 stock options

Rhea-AI Filing Summary

MIAMI INTERNATIONAL HOLDINGS, INC. executive Barbara J. Comly, EVP, GC & Corporate Secretary, exercised incentive stock options to acquire a total of 33,332 shares of Common Stock at $12.00 per share. Following these option exercises, she directly owns 845,292 shares of Common Stock.

Insights

Equity compensation analyst

Executive exercised 33,332 options and increased direct share holdings.

EVP, GC & Corporate Secretary Barbara J. Comly exercised incentive stock options covering 33,332 shares of MIAMI INTERNATIONAL HOLDINGS, INC. Common Stock at an exercise price of $12.00 per share. The options were fully vested, reflecting previously granted equity compensation.

After these exercises, she holds 845,292 Common shares directly, indicating she retained the acquired stock rather than selling it in a same-day transaction. No remaining derivative positions are shown in this record, suggesting these particular option grants have been fully exercised.

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^*

Comly Barbara J.

(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, GC & Corporate Secretary

3. Date of Earliest Transaction (Month/Day/Year)
03/09/2026

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	03/09/2026		M		8,333	A	$12	820,293	D
Common Stock	03/09/2026		M		8,333	A	$12	828,626	D
Common Stock	03/09/2026		M		16,666	A	$12	845,292	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
Incentive Stock Option (Right to Buy)	$12(1)	03/09/2026		M			8,333	(2)	08/02/2026	Common Stock	8,333	$0	0	D
Incentive Stock Option (Right to Buy)	$12(1)	03/09/2026		M			8,333	(2)	07/31/2029	Common Stock	8,333	$0	0	D
Incentive Stock Option (Right to Buy)	$12(1)	03/09/2026		M			16,666	(2)	05/28/2028	Common Stock	16,666	$0	0	D

Explanation of Responses:

1. 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.

2. The options are fully vested.

Remarks:

	/s/ Barbara J. Comly	03/10/2026
	** 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 executive Barbara J. Comly report?

Barbara J. Comly reported exercising incentive stock options to acquire 33,332 shares of MIAMI INTERNATIONAL HOLDINGS, INC. Common Stock. The options were fully vested and carried an exercise price of $12.00 per share, reflecting the use of prior equity awards to increase her share ownership.

How many MIAX shares does Barbara J. Comly hold after the reported transactions?

After the reported option exercises, Barbara J. Comly directly holds 845,292 shares of MIAMI INTERNATIONAL HOLDINGS, INC. Common Stock. This figure reflects her position following the acquisition of 33,332 shares through exercising fully vested incentive stock options at an exercise price of $12.00 per share.

What type of securities did Barbara J. Comly exercise at MIAX?

She exercised Incentive Stock Options, which are rights to buy Common Stock at a fixed price. These options, originally tied to Nonvoting Common Stock, converted into rights to buy Common Stock at $12.00 per share under the same conditions once the company’s IPO closed.

Did the MIAX Form 4 show any share sales by Barbara J. Comly?

The reported activity consists solely of exercising derivative securities to acquire Common Stock, with no sales disclosed. All transactions use code “M” for option exercises, and the summary shows acquire-side activity only, indicating the filing records option exercises rather than open-market or other share dispositions.

What is the exercise price of Barbara J. Comly’s MIAX incentive stock options?

The incentive stock options exercised by Barbara J. Comly have an exercise price of $12.00 per share. Exercising these options allowed her to purchase 33,332 shares of MIAMI INTERNATIONAL HOLDINGS, INC. Common Stock at that fixed price, increasing her direct ownership to 845,292 shares.