[Form 4] MIAMI INTERNATIONAL HOLDINGS, INC. Insider Trading Activity

MIAMI INTERNATIONAL HOLDINGS, INC. executive Shelly Brown exercised and sold shares in a planned transaction.

Rhea-AI Filing Summary

MIAMI INTERNATIONAL HOLDINGS, INC. executive Shelly Brown exercised and sold shares in a planned transaction. On April 8, 2026, Brown exercised nonqualified stock options to acquire 16,434 shares of common stock at $12.00 per share and immediately sold 16,434 shares in an open-market transaction at a weighted average price of $42.08 per share. The filing notes the options were fully vested and the trades were executed under a previously established Rule 10b5-1 Plan adopted on December 22, 2025. After these transactions, Brown directly held 325,047 shares of common stock.

Insider Trade Summary 10b5-1

Exercise and Sale: 16,434 shares ($494K approx. pre-tax spread)

Exercise and Sale 3 txns

Insider Brown Shelly

Role EVP, Chief Strategy Officer

Sold 16,434 shs ($692K)

Approx. gross sale proceeds $692K

Approx. exercise cost $197K

Approx. pre-tax spread $494K

Type	Security	Shares	Price	Value
Exercise	Nonqualified Stock Option (Right to Buy)	16,434	$0.00	$0.00
Exercise	Common Stock	16,434	$12.00	$197K
Sale	Common Stock	16,434	$42.08	$692K

Holdings After Transaction: Nonqualified Stock Option (Right to Buy) — 48,000 contracts (Direct); Common Stock — 325,047 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 22, 2025.
2. F2. This transaction was executed in multiple trades throughout the day at prices ranging from $42.00 to $42.26. The price reported above reflects the weighted average sale 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: 16,434 shares Exercise price: $12.00 per share Shares sold: 16,434 shares +4 more

7 metrics

Options exercised 16,434 shares Nonqualified stock options exercised on April 8, 2026

Exercise price $12.00 per share Strike price of nonqualified stock options

Shares sold 16,434 shares Common stock sold in open-market transaction

Weighted average sale price $42.08 per share Sales executed between $42.00 and $42.26

Post-transaction holdings 325,047 shares Common stock directly owned after April 8, 2026

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

Rule 10b5-1 plan adoption December 22, 2025 Date trading plan governing the sale was adopted

Key Terms

Nonqualified Stock Option, Rule 10b5-1 Plan, weighted average sale price, open-market sale, +1 more

5 terms

Nonqualified Stock Option financial

"security_title: "Nonqualified Stock Option (Right to Buy)""

A nonqualified stock option (NQSO) is a company grant that gives an individual the right to buy shares at a set price but does not meet special tax rules for incentive stock options; when exercised the difference between the market price and the exercise price is treated as ordinary income for the recipient and as a tax-deductible expense for the company. It matters to investors because NQSOs affect an employee’s after-tax proceeds, the company’s reported expenses, and potential share dilution—think of it like a cash bonus that converts into stock but is taxed as regular pay when you take it.

Rule 10b5-1 Plan regulatory

"transaction was effected 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 sale price financial

"The price reported above reflects the weighted average sale price."

open-market sale financial

"transaction_action: "open-market sale""

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.

fully vested financial

"The options are fully vested."

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Accepted by SEC EDGAR 04/09/2026 - 04:20 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^*

Brown Shelly

(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, Chief Strategy Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/08/2026

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	04/08/2026		M		16,434	A	$12	341,481	D
Common Stock	04/08/2026		S(1)		16,434	D	$42.08(2)	325,047	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	04/08/2026		M			16,434	(3)	08/02/2026	Common Stock	16,434	$0	48,000	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 22, 2025.

2. This transaction was executed in multiple trades throughout the day at prices ranging from $42.00 to $42.26. The price reported above reflects the weighted average sale 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	04/09/2026
	** 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)