MIAX (MIAX) EVP and CIO surrenders 32,565 shares for tax withholding

Rhea-AI Filing Summary

MIAMI INTERNATIONAL HOLDINGS, INC. executive Douglas M. Schafer Jr., EVP and CIO, reported a tax-related share disposition. He surrendered 32,565 shares of common stock at $40.79 per share to cover tax withholding and remittance obligations tied to the net settlement of restricted stock awards.

The filing states this was not an open-market sale by the reporting person. After this transaction, he directly holds 364,116 shares of common stock.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider Schafer Douglas M. JR

Role EVP and CIO

Type	Security	Shares	Price	Value
Tax Withholding	Common Stock	32,565	$40.79	$1.33M

Holdings After Transaction: Common Stock — 364,116 shares (Direct)

Footnotes (1)

1. [object Object]

Key Figures

Tax-withholding shares: 32,565 shares Reference price per share: $40.79 per share Shares held after transaction: 364,116 shares +1 more

4 metrics

Tax-withholding shares 32,565 shares Surrendered to company for tax withholding on restricted stock awards

Reference price per share $40.79 per share Value used for tax-withholding disposition of common stock

Shares held after transaction 364,116 shares Direct ownership of common stock following Form 4 transaction

Transaction code F Payment of tax liability by delivering securities

Key Terms

tax withholding, net settlement, restricted stock awards, tax-withholding disposition, +1 more

5 terms

tax withholding financial

"satisfy tax withholding and remittance obligations in connection with the net settlement"

Tax withholding is the practice of taking a portion of a payment—such as wages, dividends, or sale proceeds—before it reaches the recipient and sending that portion to the tax authority as an advance on the recipient’s eventual tax bill. For investors it matters because withholding reduces immediate cash received and affects after‑tax returns, estimated tax payments, and whether you may owe more or receive a refund when taxes are finally calculated, like having a small automatic savings set aside for your tax bill.

net settlement financial

"in connection with the net settlement of restricted stock awards"

restricted stock awards financial

"net settlement of restricted stock awards and does not represent a sale"

Restricted stock awards are company shares given to employees or executives that cannot be sold or transferred until certain conditions — like staying with the company for a set time or meeting performance targets — are met, like a gift that is locked in a safe until rules are satisfied. Investors care because these awards tie management’s pay to company performance, can increase the number of shares outstanding when they become tradable (dilution), and may signal expected future selling pressure or commitment to long-term growth.

tax-withholding disposition financial

"transaction_action": "tax-withholding disposition""

A tax-withholding disposition is an event or transaction—such as selling or transferring securities, exercising options, or receiving compensation—that triggers a requirement to hold back part of the payment and remit it to tax authorities. It matters to investors because it reduces the cash they receive immediately and can change the timing and amount of taxable income, like a cashier taking a portion of your sale proceeds to pay taxes before you get the rest.

Common Stock financial

""security_title": "Common Stock""

Common stock represents ownership shares in a company, giving investors a stake in its success and a say in important decisions through voting rights. It is the most common type of stock traded on markets and can provide income through dividends, as well as potential for value growth. For investors, holding common stock means sharing in the company’s profits and risks.

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 06/12/2026 - 04:16 PM Accepted by SEC EDGAR 06/12/2026 - 04:16 PM Learn about SEC filing dates

FAQ

What insider transaction did MIAX executive Douglas M. Schafer Jr. report?

Douglas M. Schafer Jr. reported surrendering 32,565 MIAX common shares to the company to cover tax withholding obligations from restricted stock awards, rather than selling them in the open market. This was a compensation-related, non-market transaction.

Was the MIAX Form 4 transaction a sale of shares by Douglas M. Schafer Jr.?

No, the Form 4 states the 32,565 MIAX shares were surrendered to the company to satisfy tax withholding and remittance obligations from restricted stock awards. The footnote explicitly clarifies this does not represent a sale by the reporting person.

How many MIAX shares did Douglas M. Schafer Jr. surrender for taxes and at what price?

He surrendered 32,565 MIAX common shares at a reference price of $40.79 per share to satisfy tax withholding obligations related to restricted stock awards. This transaction is coded as a tax-withholding disposition under the Form 4 rules.

How many MIAX shares does Douglas M. Schafer Jr. own after this Form 4 transaction?

Following the tax-withholding disposition, Douglas M. Schafer Jr. directly holds 364,116 MIAX common shares. This post-transaction holding reflects his remaining equity position after surrendering shares to cover associated tax obligations on restricted stock awards.

What does transaction code "F" mean in the MIAX Form 4 for Douglas M. Schafer Jr.?

Transaction code “F” indicates shares were used to pay an exercise price or tax liability. In this MIAX filing, 32,565 shares were surrendered to meet tax withholding and remittance obligations tied to restricted stock awards, not sold on the market.

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).

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^*

Schafer Douglas M. JR

(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 and CIO

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/11/2026

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	06/11/2026		F(1)		32,565	D	$40.79	364,116	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. Represents shares that have been surrendered to the Company to satisfy tax withholding and remittance obligations in connection with the net settlement of restricted stock awards and does not represent a sale by the reporting person.

Remarks:

	/s/ Alessandra Henriques Corona, Attorney-in-fact	06/12/2026
	** 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)