Miami International director sells 8,545 shares

MIAX director Judson Gray Teekell disclosed estate-related and planned open-market share sales totaling 8,545 shares, with both direct and indirect holdings remaining.

Rhea-AI Filing Summary

MIAMI INTERNATIONAL HOLDINGS, INC. (MIAX) director Judson Gray Teekell reported selling a total of 8,545 shares of common stock on September 2, 2026. This included 5,545 indirectly held shares sold in his capacity as Executor of the Estate of Byrum W. Teekell and 3,000 directly held shares sold under a previously established Rule 10b5-1 Plan. After these transactions, he reported holding 81,000 shares indirectly through the estate and 69,251 shares directly. Both sales were executed in multiple trades during the day at weighted average prices.

Insider Trade Summary 10b5-1

Net Seller: 8,545 shares

Net Sell 2 txns

Insider Teekell Judson Gray

Role Director

Sold 8,545 shs ($353K)

Type	Security	Shares	Price	Value
Sale	Common Stock F1, F2	5,545	$41.58	$231K
Sale	Common Stock F3, F4	3,000	$40.89	$123K

Holdings After Transaction: Common Stock — 81,000 shares (Indirect, By estate of Byrum W. Teekell); Common Stock — 69,251 shares (Direct)

Footnotes (4)

1. F1. This transaction involved a sale by the Reporting Person in connection with his duties as Executor of the Estate of Byrum W. Teekell.
2. F2. This transaction was executed in multiple trades throughout the day at prices ranging from $41.02 to $41.80. 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. This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 17, 2025.
4. F4. This transaction was executed in multiple trades throughout the day at prices ranging from $40.31 to $41.53. 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.

Key Figures

Shares sold (estate-related): 5,545 shares Weighted average sale price (estate-related): $41.58 per share Indirect holdings after transaction: 81,000 shares +4 more

7 metrics

Shares sold (estate-related) 5,545 shares Common stock sold indirectly through the Estate of Byrum W. Teekell on September 2, 2026

Weighted average sale price (estate-related) $41.58 per share Estate-related sale of 5,545 shares, with trade prices from $41.02 to $41.80

Indirect holdings after transaction 81,000 shares MIAX common stock held indirectly through the Estate of Byrum W. Teekell after the sale

Shares sold (direct) 3,000 shares Directly held MIAX common stock sold on September 2, 2026 under a Rule 10b5-1 Plan

Weighted average sale price (direct) $40.89 per share Direct sale of 3,000 shares, with trade prices from $40.31 to $41.53

Direct holdings after transaction 69,251 shares MIAX common stock held directly by Judson Gray Teekell after the sale

Rule 10b5-1 Plan adoption date December 17, 2025 Plan under which the 3,000-share direct sale on September 2, 2026 was effected

Key Terms

Rule 10b5-1 Plan, Executor, weighted average sales price

3 terms

Rule 10b5-1 Plan regulatory

"This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 17, 2025."

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.

Executor other

"This transaction involved a sale by the Reporting Person in connection with his duties as Executor of the Estate of Byrum W. Teekell."

weighted average sales price financial

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

FAQ

Who conducted the insider transactions reported for MIAX?

The transactions were reported by director Judson Gray Teekell of MIAMI INTERNATIONAL HOLDINGS, INC., involving both directly held shares and shares held indirectly through the Estate of Byrum W. Teekell.

How many MIAX shares did Judson Gray Teekell sell on September 2, 2026?

On September 2, 2026, Judson Gray Teekell reported selling 8,545 shares of MIAX common stock: 5,545 shares held indirectly through an estate and 3,000 shares held directly.

At what prices were the MIAX shares sold by Judson Gray Teekell?

The estate-related sale had a weighted average price of $41.58 per share, with trades from $41.02 to $41.80. The direct sale had a weighted average price of $40.89 per share, with trades from $40.31 to $41.53.

How many MIAX shares does Judson Gray Teekell report owning after these sales?

After the reported sales, Judson Gray Teekell reported holding 81,000 MIAX shares indirectly through the Estate of Byrum W. Teekell and 69,251 MIAX shares directly.

Was a Rule 10b5-1 trading plan involved in the MIAX insider sales?

Yes. The direct sale of 3,000 MIAX shares on September 2, 2026 was effected pursuant to a previously established Rule 10b5-1 Plan adopted by Judson Gray Teekell on December 17, 2025.

What is the nature of the estate-related MIAX share sale?

The sale of 5,545 MIAX shares was made in connection with Judson Gray Teekell’s duties as Executor of the Estate of Byrum W. Teekell, and the shares are reported as held indirectly by that estate.

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Available on EDGAR 09/04/2026 - 04:22 PM Accepted by SEC EDGAR 09/04/2026 - 04:21 PM 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^*

Teekell Judson Gray

(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)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/02/2026

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	09/02/2026		S(1)		5,545	D	$41.58(2)	81,000	I	By estate of Byrum W. Teekell
Common Stock	09/02/2026		S(3)		3,000	D	$40.89(4)	69,251	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

Explanation of Responses:

1. This transaction involved a sale by the Reporting Person in connection with his duties as Executor of the Estate of Byrum W. Teekell.

2. This transaction was executed in multiple trades throughout the day at prices ranging from $41.02 to $41.80. 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. This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 17, 2025.

4. This transaction was executed in multiple trades throughout the day at prices ranging from $40.31 to $41.53. 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.

Remarks:

	/s/Alessandra Maria Corona Henriques, Attorney-in-Fact	09/04/2026
	** 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)