SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person* STAHL MURRAY (Last) (First) (Middle) 470 PARK AVE S 8TH FLOOR SOUTH (Street) NEW YORK NY 10016 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 08/13/2025	3. Issuer Name and Ticker or Trading Symbol MIAMI INTERNATIONAL HOLDINGS, INC. [ MIAX ]
		4. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director 10% Owner Officer (give title below) Other (specify below)	5. If Amendment, Date of Original Filed (Month/Day/Year)
			6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	4,196,752	I(1)(2)	Horizon Kinetics Asset Management LLC

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
OPTIONS	08/13/2025	05/31/2031	Miami International Holdings Inc	2,500	$16.14(3)	D
OPTIONS	08/13/2025	07/31/2031	Miami International Holdings Inc	7,500	$16.14(3)	D
OPTIONS	08/13/2025	06/30/2032	Miami International Holdings Inc	10,000	$25.98(3)	D
OPTIONS	08/13/2025	03/26/2033	Miami International Holdings Inc	14,331	$19.84(3)	D
Warrants	08/13/2025	11/15/2026	Miami International Holdings Inc	24,878	$20.5(1)(4)	I	Horizon Kinetics Asset Management LLC
Warrants	08/13/2025	02/05/2027	Miami International Holdings Inc	27,561	$20.5(1)(4)	I	Horizon Kinetics Asset Management LLC
Warrants	08/13/2025	04/08/2026	Miami International Holdings Inc	21,290	$15(1)(4)	I	Horizon Kinetics Asset Management LLC
Warrants	08/13/2025	10/17/2026	Miami International Holdings Inc	38,927	$20.5(1)(4)	I	Horizon Kinetics Asset Management LLC

1. Name and Address of Reporting Person* STAHL MURRAY (Last) (First) (Middle) 470 PARK AVE S 8TH FLOOR SOUTH (Street) NEW YORK NY 10016 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* HORIZON KINETICS ASSET MANAGEMENT LLC (Last) (First) (Middle) 470 PARK AVE S 8TH FLOOR SOUTH (Street) NEW YORK NY 10016 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. Murray Stahl serves as Chairman, Chief Executive Officer, and Chief Investment Officer of Horizon Kinetics Asset Management LLC ("HKAM"), which manages funds and accounts (the "Managed Accounts") that hold securities of the Issuer. Mr. Stahl does not exercise investment discretion with respect to the securities of the Issuer that are beneficially owned by the Managed Accounts. Mr. Stahl disclaims beneficial ownership over the securities reported, except to the extent of his pecuniary interest therein, if any. The filing of this Form shall not be deemed an admission that the Mr. Stahl is the beneficial owner of such securities for purposes of Section 16 or any other purpose.

2. Of the 4,196,752 shares owned; 5,000 shares are Series B, and 15,000 shares are Restricted and Exercised Non-Voting. The shares of Series B Preferred Stock are convertible on a one-for-one basis into shares of common stock commencing on the Company's initial public offering of its common stock ("IPO") effective date, which is August 13, 2025. The Series B Preferred Stock has no expiration date. The Restricted and Exercised Non-Voting shares are convertible on a one-for-one basis into shares of common stock commencing at any time. The Non-Voting common stock has no expiration date

3. The options given to Mr. Stahl are fully vested. The options were granted initially as the right to buy nonvoting common stock. On the closing date of the Company's IPO of its common stock, these will convert to the right to buy common stock instead of nonvoting common stock.

4. The warrants are currently vested and presently exercisable until the expiration date shown.

	/s/ Jay Kesslen, attorney-in-fact	08/13/2025
	** Signature of Reporting Person	Date
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