Miami Int'l (MIAX) Insider Exercises Options, Net-Settles 1,980 Shares for Taxes

Rhea-AI Filing Summary

Jayabalan Harish, EVP, CISO and CRO of Miami International Holdings, Inc. (MIAX), reported option exercises and resulting share ownership changes on 09/09/2025. He exercised 21,999 incentive stock options and 3,001 nonqualified stock options at a $12 exercise price, resulting in 25,000 shares acquired that day. The filing shows 72,384 shares beneficially owned after the first reported acquisition line and 75,385 after the second; a separate line records a net disposition of 1,980 shares at $37.30 representing shares surrendered to satisfy tax withholding on the net settlement of exercised options (not a sale). The reporting was signed by an attorney-in-fact on 09/11/2025.

Positive

• Exercise of fully vested options (21,999 incentive and 3,001 nonqualified) shows insider confidence in realizing company equity value
• Net settlement disclosure clarifies that 1,980 shares were surrendered solely for tax withholding, not sold on the open market

Negative

• None.

Insights

Financial Analyst

TL;DR: Insider exercised vested options adding 25,000 shares; modest increase in insider stake, routine compensation-related activity.

The reporting person exercised fully vested options (21,999 incentive; 3,001 nonqualified) at a $12 strike on 09/09/2025, creating 25,000 underlying shares. The filing documents the surrender of 1,980 shares to cover tax withholding related to net settlement rather than an open-market sale. For investors this indicates management is realizing option value but also retaining a substantial position (reported beneficial ownership in the ~73k–75k range). This is a standard Section 16 disclosure with no disclosed sale proceeds or diversification intent.

Corporate Governance Expert

TL;DR: Transaction reflects routine exercise of vested equity compensation and tax withholding; disclosure appears complete and timely.

The Form 4 shows exercises of fully vested options and subsequent net settlement mechanics (surrender of shares for tax withholding). The filing identifies the reporting person as an officer (EVP, CISO and CRO) and was signed by an attorney-in-fact. There are no indications of rule 10b5-1 plans or open-market sales in this filing. From a governance perspective, this is consistent with equity remuneration and required insider reporting obligations.

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^*

Jayabalan Harish

(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, CISO and CRO

3. Date of Earliest Transaction (Month/Day/Year)
09/09/2025

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	09/09/2025		M		21,999	A	$12	72,384	D
Common Stock	09/09/2025		M		3,001	A	$12	75,385	D
Common Stock	09/09/2025		F		1,980(1)	D	$37.3	73,405	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	09/09/2025		M			21,999	(2)	09/17/2025	Common Stock	21,999	$0	0	D
Nonqualified Stock Option (Right to Buy)	$12	09/09/2025		M			3,001	(2)	09/17/2025	Common Stock	3,001	$0	0	D

Explanation of Responses:

1. Represents shares that have been surrendered to the Company to satisfy tax withholding and remittance obligations in connection with the net settlement of options exercised and does not represent a sale by the reporting person.

2. The options are fully vested.

Remarks:

	/s/Alessandra Maria Corona Henriques, Attorney-in-Fact	09/11/2025
	** 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 transactions did Jayabalan Harish report on Form 4 for MIAX?

He reported exercising 21,999 incentive and 3,001 nonqualified stock options on 09/09/2025, and surrendering 1,980 shares to cover tax withholding.

At what price were the stock options exercised?

The options were exercised at an exercise price of $12.00 per share.

Did the reporting person sell shares on the open market?

No. The Form 4 states the 1,980 shares were surrendered to the company to satisfy tax withholding related to net settlement, and are not a sale by the reporting person.

How many shares did the insider beneficially own after the transactions?

The filing lists beneficial ownership levels of 72,384, 75,385, and 73,405 across reported lines after the respective transactions.

Were the exercised options vested at the time of exercise?

Yes. The filing states the options were fully vested.