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*
STAHL MURRAY

(Last) (First) (Middle)
470 PARK AVE S
8TH FLOOR SOUTH

(Street)
NEW YORK NY 10016

(City) (State) (Zip)
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)
3. Date of Earliest Transaction (Month/Day/Year)
03/02/2026
4. 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 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 03/02/2026 X(1) 21,290 A $15 4,581,654 I Horizon Kinetics Asset Management LLC
Common Stock 03/02/2026 X(1) 91,366 A $20.5 4,673,020 I Horizon Kinetics Asset Management LLC
Common Stock 03/02/2026 X(1) 137,500 A $20 4,810,520 I Horizon Kinetics Asset Management LLC
Common Stock 03/02/2026 S(1) 121,054 D $40.92 4,689,466 I Horizon Kinetics Asset Management LLC
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
Warrant (right to buy) $15 03/02/2026 X 21,290 08/13/2025 04/08/2026 Common Stock 21,290 $0 0 I Horizon Kinetics Asset Management LLC
Warrant (right to buy) $20.5 03/02/2026 X 24,878 08/13/2025 11/15/2026 Common Stock 24,878 $0 0 I Horizon Kinetics Asset Management LLC
Warrant (right to buy) $20.5 03/02/2026 X 27,561 08/13/2025 02/05/2027 Common Stock 27,561 $0 0 I Horizon Kinetics Asset Management LLC
Warrant (right to buy) $20.5 03/02/2026 X 38,927 08/13/2025 10/17/2026 Common Stock 38,927 $0 0 I Horizon Kinetics Asset Management LLC
Warrant (right to buy) $20 03/02/2026 X 137,500 08/13/2025 08/09/2027 Common Stock 137,500 $0 0 I Horizon Kinetics Asset Management LLC
Options $16.14(2) 08/13/2025 07/31/2031 Miami International Holdings Inc 7,500 7,500 D
Options $25.98(2) 08/13/2025 06/30/2032 Miami International Holdings Inc 10,000 10,000 D
Options $19.84(2) 08/13/2025 03/26/2033 Miami International Holdings Inc 14,331 14,331 D
Options $16.14(2) 08/13/2025 05/31/2031 Miami International Holdings Inc 2,500 2,500 D
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. Horizon Kinetics Asset Management LLC (HKAM) exercised warrants to purchase 341,522 shares of common stock at the exercise prices noted. HKAM paid the exercise price on a cashless basis, resulting in the Issuer withholding 121,054 of the warrant shares to pay the exercise price and issuing to HKAM the remaining 129,102 shares.
2. The Options given to Mr. Stahl are fully vested.
/s/Jay Kesslen, attorney-in-fact 03/03/2026
** 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.