X0508 4/A 2026-03-02 2026-03-04 0001438472 MIAMI INTERNATIONAL HOLDINGS, INC. MIAX 0001207097 STAHL MURRAY 470 PARK AVE S 8TH FLOOR SOUTH NEW YORK NY 10016 1 0001056823 HORIZON KINETICS ASSET MANAGEMENT LLC 470 PARK AVE S 8TH FLOOR SOUTH NEW YORK NY 10016 1 0 Common Stock 2026-03-02 4 X 0 21290 15 A 4581654 I Horizon Kinetics Asset Management LLC Common Stock 2026-03-02 4 X 0 91366 20.50 A 4673020 I Horizon Kinetics Asset Management LLC Common Stock 2026-03-02 4 S 0 53578 40.92 D 4619442 I Horizon Kinetics Asset Management LLC Warrant (right to buy) 15 2026-03-02 4 X 0 21290 0 D 2025-08-13 2026-04-08 Common Stock 21290 0 I Horizon Kinetics Asset Management LLC Warrant (right to buy) 20.50 2026-03-02 4 X 0 24878 0 D 2025-08-13 2026-11-15 Common Stock 24878 0 I Horizon Kinetics Asset Management LLC Warrant (right to buy) 20.50 2026-03-02 4 X 0 27561 0 D 2025-08-13 2027-02-05 Common Stock 27561 0 I Horizon Kinetics Asset Management LLC Warrant (right to buy) 20.50 2026-03-02 4 X 0 38927 0 D 2025-08-13 2026-10-17 Common Stock 38927 0 I Horizon Kinetics Asset Management LLC Options 16.1400 2025-08-13 2031-07-31 Miami International Holdings Inc 7500 7500 D Options 25.9800 2025-08-13 2032-06-30 Miami International Holdings Inc 10000 10000 D Options 19.8400 2025-08-13 2033-03-26 Miami International Holdings Inc 14331 14331 D Options 16.1400 2025-08-13 2031-05-31 Miami International Holdings Inc 2500 2500 D This amendment corrects a previous filing that inadvertently included shares that are not subject to reporting and also corrects the share totals. Horizon Kinetics Asset Management LLC (HKAM) exercised warrants to purchase 112,656 shares of common stock at the exercise prices noted. HKAM paid the exercise price on a cashless basis, resulting in the Issuer withholding 53,578 of the warrant shares to pay the exercise price and issuing to HKAM the remaining 59,078 shares. The Options given to Mr. Stahl are fully vested. /s/Jay Kesslen, attorney-in-fact 2026-03-06