MIAX executive sells 4,714 shares under 10b5-1 plan

MIAMI INTERNATIONAL HOLDINGS, INC. executive Shelly Brown, EVP and Chief Strategy Officer, sold 4,714 shares of common stock in an open-market transaction at a weighted average price of $44.23 per share.

Rhea-AI Filing Summary

MIAMI INTERNATIONAL HOLDINGS, INC. executive Shelly Brown, EVP and Chief Strategy Officer, sold 4,714 shares of common stock in an open-market transaction at a weighted average price of $44.23 per share. The sale was made under a previously established Rule 10b5-1 trading plan adopted on December 22, 2025. Following this transaction, Brown directly holds 316,714 shares of MIAX common stock.

Insider Trade Summary 10b5-1

Net Seller: 4,714 shares

Net Sell 1 txn

Insider Brown Shelly

Role EVP, Chief Strategy Officer

Sold 4,714 shs ($209K)

Type	Security	Shares	Price	Value
Sale	Common Stock	4,714	$44.23	$209K

Holdings After Transaction: Common Stock — 316,714 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 22, 2025.
2. F2. This transaction was executed in multiple trades throughout the day at prices ranging from $43.36 to $45.04. 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: 4,714 shares Average sale price: $44.23 per share Price range: $43.36–$45.04 per share +2 more

5 metrics

Shares sold 4,714 shares Open-market sale of common stock on June 15, 2026

Average sale price $44.23 per share Weighted average price across multiple trades

Price range $43.36–$45.04 per share Execution range for trades on the sale date

Shares owned after sale 316,714 shares Direct holdings following the reported transaction

Net shares sold 4,714 shares Net selling activity in transaction summary

Key Terms

Rule 10b5-1 Plan, open-market sale, weighted average sales price, non-derivative

4 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 22, 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.

open-market sale financial

"transaction_action: "open-market sale" and code description "Sale in open market or private transaction""

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.

weighted average sales price financial

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

non-derivative financial

"transaction_type: "non-derivative" for the common stock transaction"

FAQ

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

What insider transaction did MIAX executive Shelly Brown report on this Form 4?

Shelly Brown reported selling 4,714 shares of MIAX common stock in an open-market transaction. The weighted average sale price was $44.23 per share, based on multiple trades executed between $43.36 and $45.04 during the same trading day.

What is Shelly Brown’s remaining MIAX share ownership after this reported sale?

After selling 4,714 shares, Shelly Brown directly owns 316,714 shares of MIAX common stock. This figure reflects her direct holdings immediately following the reported open-market transaction on June 15, 2026, as disclosed in the Form 4 filing.

Was Shelly Brown’s MIAX stock sale made under a Rule 10b5-1 trading plan?

Yes. The Form 4 states the transaction was executed under a previously established Rule 10b5-1 Plan adopted on December 22, 2025. Such plans pre-schedule trades, helping separate routine portfolio management from discretionary timing decisions by insiders.

At what prices were Shelly Brown’s MIAX shares actually sold on the transaction date?

Although the Form 4 reports a weighted average price of $44.23 per share, it notes the shares were sold in multiple trades at prices ranging from $43.36 to $45.04. The reporting person offers to provide exact trade details upon request.

Does this MIAX Form 4 indicate any option exercises or derivative transactions?

No. The Form 4 describes a single non-derivative open-market sale of common stock by Shelly Brown. The derivative summary section shows no option exercises or other derivative transactions associated with this particular filing and transaction date.

How many MIAX shares did Shelly Brown sell in total according to this Form 4?

The filing shows that Shelly Brown sold a total of 4,714 MIAX common shares. This amount also appears as the net selling activity in the transaction summary, where net buy/sell shares are reported as negative 4,714, indicating net sales.

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

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Accepted by SEC EDGAR 06/17/2026 - 04:08 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)
06/15/2026

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	06/15/2026		S(1)		4,714	D	$44.23(2)	316,714	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 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 $43.36 to $45.04. 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	06/17/2026
	** 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)