Miami International Holdings' Comly sells 12,306 shares

The EVP, GC & Corporate Secretary sold the acquired shares under a Rule 10b5-1 Plan adopted December 18, 2025.

Rhea-AI Filing Summary

At MIAMI INTERNATIONAL HOLDINGS, INC., EVP, GC & Corporate Secretary Barbara J. Comly exercised 12,306 fully vested nonqualified stock options on October 22, 2026, acquiring 12,306 common shares at $12 per share, then sold 12,306 shares at a weighted average of $35.04 per share. The sale was made under a previously established Rule 10b5-1 Plan adopted December 18, 2025; the reported option balance after exercise was 32,138 shares. Sale trades ranged from $35.00 to $35.14 per share.

Insider Trade Summary 10b5-1

Exercise and Sale: 12,306 shares ($284K approx. pre-tax spread)

Exercise and Sale 3 txns

Insider Comly Barbara J.

Role EVP, GC & Corporate Secretary

Sold 12,306 shs ($431K)

Approx. gross sale proceeds $431K

Approx. exercise cost $148K

Approx. pre-tax spread $284K

Type	Security	Shares	Price	Value
Exercise	Nonqualified Stock Option (Right to Buy) F1, F3	12,306	$0.00	$0.00
Exercise	Common Stock F1	12,306	$12.00	$148K
Sale	Common Stock F1, F2	12,306	$35.04	$431K

Holdings After Transaction: Nonqualified Stock Option (Right to Buy) — 32,138 contracts (Direct); Common Stock — 839,564 shares (Direct)

Footnotes (3)

1. F1. This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025.
2. F2. This transaction was executed in multiple trades throughout the day at prices ranging from $35.00 to $35.14. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected.
3. F3. The options are fully vested.

Key Figures

Options exercised: 12,306 options Exercise price: $12 per share Common shares acquired: 12,306 shares +4 more

7 metrics

Options exercised 12,306 options October 22, 2026

Exercise price $12 per share Options exercised October 22, 2026

Common shares acquired 12,306 shares October 22, 2026

Common shares sold 12,306 shares October 22, 2026

Weighted average sale price $35.04 per share Sale on October 22, 2026

Sale price range $35.00 to $35.14 per share Multiple trades throughout October 22, 2026

Option shares following exercise 32,138 shares Reported after the October 22, 2026 exercise

Key Terms

Nonqualified Stock Option (Right to Buy), Rule 10b5-1 Plan, weighted average sales price

3 terms

Nonqualified Stock Option (Right to Buy) financial

"Nonqualified Stock Option (Right to Buy)"

Rule 10b5-1 Plan financial

"pursuant to a previously established Rule 10b5-1 Plan"

A Rule 10b5-1 plan is a prearranged, written schedule that lets corporate insiders buy or sell company stock at set times or amounts, even if they later learn material nonpublic information. Think of it like setting an automatic thermostat for trades: it creates a clear record that trades were planned in advance, reducing the risk of insider-trading accusations and helping investors trust that insider transactions are routine rather than based on secret information.

weighted average sales price financial

"reflects the weighted average sales price"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

How many MIAX shares did Barbara J. Comly sell?

Barbara J. Comly sold 12,306 common shares on October 22, 2026, at a weighted average price of $35.04 per share. Trades ranged from $35.00 to $35.14 per share, and the sale was made under a Rule 10b5-1 Plan adopted December 18, 2025.

What MIAX options did Barbara J. Comly exercise?

She exercised 12,306 fully vested nonqualified stock options on October 22, 2026, at an exercise price of $12 per share, acquiring 12,306 common shares.

How many option shares were reported after Barbara J. Comly's exercise?

The reported option balance following the exercise was 32,138 shares.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 10/26/2026 - 04:06 PM EDT Accepted by SEC EDGAR 10/26/2026 - 04:06 PM EDT Learn about SEC filing dates

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
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

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 NEW JERSEY 08540

(City) (State) (Zip)

UNITED STATES

(Country)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
10/22/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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	10/22/2026		M(1)		12,306	A	$12	851,870	D
Common Stock	10/22/2026		S(1)		12,306	D	$35.04(2)	839,564	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
Nonqualified Stock Option (Right to Buy)	$12	10/22/2026		M(1)			12,306	(3)	05/28/2028	Common Stock	12,306	$0	32,138	D

Explanation of Responses:

1. This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 18, 2025.

2. This transaction was executed in multiple trades throughout the day at prices ranging from $35.00 to $35.14. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected.

3. The options are fully vested.

Remarks:

	/s/Alessandra Maria Corona Henriques, Attorney-in-Fact	10/26/2026
	** 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.
* Form 4: SEC 1474 (03-26)