Miami International CIO sells 8,000 shares after exercise

Q: How many MIAX shares did the EVP and CIO exercise and sell?

Douglas M. Schafer Jr. exercised 8,000 options at $12 per share for 8,000 common shares on October 22, 2026, then sold all 8,000 shares at a weighted average price of $35.06 per share. The transactions were made under a Rule 10b5-1 Plan adopted December 16, 2025.

The EVP and CIO’s sale involved multiple trades priced from $35.00 to $35.14 under a plan adopted December 16, 2025.

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Form Type

Rhea-AI Filing Summary

MIAMI INTERNATIONAL HOLDINGS, INC. (MIAX) reported that its EVP and CIO, Douglas M. Schafer Jr., exercised 8,000 fully vested options at $12 per share on October 22, 2026, acquiring 8,000 common shares and selling all 8,000 at a weighted average of $35.06 per share. The transactions were effected under a previously established Rule 10b5-1 Plan adopted December 16, 2025. The reported option position following the exercise covered 147,334 shares and expires July 31, 2029.

Insider Trade Summary 10b5-1

Exercise and Sale: 8,000 shares ($184K approx. pre-tax spread)

Exercise and Sale 3 txns

Insider Schafer Douglas M. JR

Role EVP and CIO

Sold 8,000 shs ($280K)

Approx. gross sale proceeds $280K

Approx. exercise cost $96K

Approx. pre-tax spread $184K

Type	Security	Shares	Price	Value
Exercise	Nonqualified Stock Option (Right to Buy) ^{F1, F3}	8,000	$0.00	$0.00
Exercise	Common Stock ^F1	8,000	$12.00	$96K
Sale	Common Stock ^{F1, F2}	8,000	$35.06	$280K

Holdings After Transaction: Nonqualified Stock Option (Right to Buy) — 147,334 contracts (Direct); Common Stock — 387,414 shares (Direct)

Footnotes (3)

F1. This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 16, 2025.
F2. This transaction was executed in multiple trades throughout the day at prices ranging from $35.00 to $35.14. 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.
F3. The options are fully vested.

Key Figures

Options exercised: 8,000 options Exercise price: $12 per share Common shares acquired: 8,000 shares +3 more

6 metrics

Options exercised 8,000 options October 22, 2026

Exercise price $12 per share Options exercised October 22, 2026

Common shares acquired 8,000 shares On exercise of options on October 22, 2026

Shares sold 8,000 shares October 22, 2026

Weighted average sales price $35.06 per share Sale on October 22, 2026

Shares underlying reported option position 147,334 shares Following the October 22, 2026 transaction; options expire July 31, 2029

Key Terms

Rule 10b5-1 Plan, Nonqualified Stock Option (Right to Buy), weighted average sales price, fully vested

4 terms

Rule 10b5-1 Plan regulatory

"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.

Nonqualified Stock Option (Right to Buy) financial

"Nonqualified Stock Option (Right to Buy)"

weighted average sales price financial

"weighted average sales price"

fully vested financial

"The options are fully vested."

FAQ

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

How many MIAX shares did the EVP and CIO exercise and sell?

Douglas M. Schafer Jr. exercised 8,000 options at $12 per share for 8,000 common shares on October 22, 2026, then sold all 8,000 shares at a weighted average price of $35.06 per share. The transactions were made under a Rule 10b5-1 Plan adopted December 16, 2025.

What options remained after the MIAX EVP and CIO's exercise?

Following the October 22, 2026 exercise, the reported option position covered 147,334 shares and expired July 31, 2029.

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

Form 4 Insider Transactions: What Each Field Means →

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Available on EDGAR 10/26/2026 - 04:05 PM EDT Accepted by SEC EDGAR 10/26/2026 - 04:05 PM EDT

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)
10/22/2026

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	10/22/2026		M⁽¹⁾		8,000	A	$12	395,414	D
Common Stock	10/22/2026		S⁽¹⁾		8,000	D	$35.06⁽²⁾	387,414	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Nonqualified Stock Option (Right to Buy)	$12	10/22/2026		M⁽¹⁾			8,000	⁽³⁾	07/31/2029	Common Stock	8,000	$0	147,334	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 16, 2025.

2. This transaction was executed in multiple trades throughout the day at prices ranging from $35.00 to $35.14. 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. The options are fully vested.

Remarks:

	/s/ Alessandra Henriques Corona, Attorney-in-fact	10/26/2026
	** 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)

Source: View Original Filing on SEC EDGAR