MIAMI International EVP sells shares after option exercise

MIAMI International Holdings EVP, GC & Corporate Secretary Barbara J. Comly reported an exercise-and-sell transaction in company common stock.

Rhea-AI Filing Summary

MIAMI International Holdings EVP, GC & Corporate Secretary Barbara J. Comly reported an exercise-and-sell transaction in company common stock. On May 4, 2026, she exercised 28,000 nonqualified stock options at $12.00 per share and acquired the same number of common shares.

On the same date, she executed an open-market sale of 28,000 common shares at an average price of $47.26 per share, pursuant to a pre-established Rule 10b5-1 Plan adopted on December 18, 2025. Following these transactions, she directly holds 843,844 common shares and 84,000 nonqualified stock options that are reported as fully vested.

Insider Trade Summary 10b5-1

Exercise and Sale: 28,000 shares ($987K approx. pre-tax spread)

Exercise and Sale 3 txns

Insider Comly Barbara J.

Role EVP, GC & Corporate Secretary

Sold 28,000 shs ($1.32M)

Approx. gross sale proceeds $1.32M

Approx. exercise cost $336K

Approx. pre-tax spread $987K

Type	Security	Shares	Price	Value
Exercise	Nonqualified Stock Option (Right to Buy)	28,000	$0.00	$0.00
Exercise	Common Stock	28,000	$12.00	$336K
Sale	Common Stock	28,000	$47.26	$1.32M

Holdings After Transaction: Nonqualified Stock Option (Right to Buy) — 84,000 contracts (Direct); Common Stock — 843,844 shares (Direct)

Footnotes (2)

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. The options are fully vested.

Key Figures

Shares sold: 28,000 shares Sale price per share: $47.26 per share Options exercised: 28,000 options +5 more

8 metrics

Shares sold 28,000 shares Open-market sale of common stock on May 4, 2026

Sale price per share $47.26 per share Average price for 28,000 common shares sold

Options exercised 28,000 options Nonqualified stock options exercised into common shares

Option exercise price $12.00 per share Exercise price of nonqualified stock options

Shares held after 843,844 shares Direct common stock holdings after transactions

Options outstanding after 84,000 options Nonqualified stock options remaining and fully vested

Rule 10b5-1 plan adoption date December 18, 2025 Date pre-arranged trading plan was adopted

Option expiration date August 2, 2026 Expiration of exercised nonqualified stock option grant

Key Terms

Rule 10b5-1 Plan, Nonqualified Stock Option (Right to Buy), open-market sale, derivative security, +1 more

5 terms

Rule 10b5-1 Plan regulatory

"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person"

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.

Nonqualified Stock Option (Right to Buy) financial

"security_title: Nonqualified Stock Option (Right to Buy) with an exercise price of $12.0000"

open-market sale financial

"transaction_action: open-market sale of 28,000 shares of Common Stock"

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

derivative security financial

"transaction_code_description: Exercise or conversion of derivative security"

A derivative security is a financial contract whose value comes from the price or performance of something else, such as a stock, bond, commodity, or market index. For investors it acts like an insurance policy or a wager: it can be used to protect against losses, lock in prices, or amplify gains and losses, so it can change a portfolio’s risk and potential return without owning the underlying asset directly.

fully vested financial

"footnote: The options are fully vested."

FAQ

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

What did MIAX executive Barbara J. Comly report in this Form 4 filing?

Barbara J. Comly reported exercising nonqualified stock options and selling common stock. She exercised 28,000 options for MIAX common shares, then sold 28,000 shares in an open-market transaction while retaining a sizeable remaining equity position in the company.

Was Barbara J. Comly’s MIAX stock sale made under a Rule 10b5-1 plan?

Yes. The filing states the transaction was effected under a pre-established Rule 10b5-1 Plan adopted on December 18, 2025. Such plans pre-schedule trades, indicating the timing of this sale was determined in advance rather than decided opportunistically.

At what prices did Barbara J. Comly exercise options and sell MIAX shares?

She exercised 28,000 nonqualified stock options at an exercise price of $12.00 per share. On the same date, she sold 28,000 common shares in the open market at an average price of $47.26 per share, according to the transaction details disclosed.

How many MIAX shares does Barbara J. Comly own after these transactions?

After the reported transactions, she directly holds 843,844 shares of MIAX common stock. The filing also shows 84,000 nonqualified stock options outstanding and fully vested, indicating she maintains significant continuing equity exposure to the company.

What type of derivative security did Barbara J. Comly exercise in this MIAX filing?

She exercised a nonqualified stock option, described as a “Nonqualified Stock Option (Right to Buy).” This derivative gave her the right to purchase 28,000 MIAX common shares at a fixed $12.00 exercise price before its stated expiration date.

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

Form 4 Insider Transactions: What Each Field Means →

See more from StockTitan in Google Search and AI answers. Adds StockTitan as a preferred source · opens Google

Add on Google Not now

Accepted by SEC EDGAR 05/05/2026 - 07:30 AM 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)
05/04/2026

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	05/04/2026		M(1)		28,000	A	$12	871,844	D
Common Stock	05/04/2026		S(1)		28,000	D	$47.26	843,844	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	05/04/2026		M(1)			28,000	(2)	08/02/2026	Common Stock	28,000	$0	84,000	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. The options are fully vested.

Remarks:

	/s/Alessandra Maria Corona Henriques, Attorney-in-Fact	05/05/2026
	** 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)