Murray Stahl - 02 Mar 2026 Form 4/A - Amendment Insider Report for MIAMI INTERNATIONAL HOLDINGS, INC. (MIAX)

Role: Director
Signature: /s/Jay Kesslen, attorney-in-fact
Issuer symbol: MIAX
Transactions as of: 02 Mar 2026
Net transactions value: -$2,192,412
Form type: 4/A - Amendment
Filing time: 06 Mar 2026, 16:12:14 UTC
Date Of Original Report: 04 Mar 2026
Previous filing: 02 Mar 2026
Next filing: 04 Mar 2026
SEC: View on sec.gov

Reporting Owners (2)

Name	Relationship	Address	Signature	Signature date	CIK
STAHL MURRAY	Director	470 PARK AVE S, 8TH FLOOR SOUTH, NEW YORK	/s/Jay Kesslen, attorney-in-fact	06 Mar 2026	0001207097
HORIZON KINETICS ASSET MANAGEMENT LLC	10%+ Owner	470 PARK AVE S, 8TH FLOOR SOUTH, NEW YORK	/s/Jay Kesslen, attorney-in-fact	06 Mar 2026	0001056823

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	MIAX	Common Stock	Exercise of in-the-money or at-the-money derivative security		+21,290	+0.47%	$15.00^*	4,581,654	02 Mar 2026	Horizon Kinetics Asset Management LLC	F1
transaction	MIAX	Common Stock	Exercise of in-the-money or at-the-money derivative security		+91,366	+2%	$20.50^*	4,673,020	02 Mar 2026	Horizon Kinetics Asset Management LLC	F1
transaction	MIAX	Common Stock	Sale	$2,192,412	-53,578	-1.1%	$40.92	4,619,442	02 Mar 2026	Horizon Kinetics Asset Management LLC	F1

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	MIAX	Warrant (right to buy)	Exercise of in-the-money or at-the-money derivative security	-21,290	-100%	$0.000000^*	0	02 Mar 2026	Common Stock	21,290	$15.00	Horizon Kinetics Asset Management LLC
transaction	MIAX	Warrant (right to buy)	Exercise of in-the-money or at-the-money derivative security	-24,878	-100%	$0.000000^*	0	02 Mar 2026	Common Stock	24,878	$20.50	Horizon Kinetics Asset Management LLC
transaction	MIAX	Warrant (right to buy)	Exercise of in-the-money or at-the-money derivative security	-27,561	-100%	$0.000000^*	0	02 Mar 2026	Common Stock	27,561	$20.50	Horizon Kinetics Asset Management LLC
transaction	MIAX	Warrant (right to buy)	Exercise of in-the-money or at-the-money derivative security	-38,927	-100%	$0.000000^*	0	02 Mar 2026	Common Stock	38,927	$20.50	Horizon Kinetics Asset Management LLC
holding	MIAX	Options					7,500	02 Mar 2026	Miami International Holdings Inc	7,500	$16.14	Direct	F2
holding	MIAX	Options					10,000	02 Mar 2026	Miami International Holdings Inc	10,000	$25.98	Direct	F2
holding	MIAX	Options					14,331	02 Mar 2026	Miami International Holdings Inc	14,331	$19.84	Direct	F2
holding	MIAX	Options					2,500	02 Mar 2026	Miami International Holdings Inc	2,500	$16.14	Direct	F2

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	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.
F2	The Options given to Mr. Stahl are fully vested.

Content

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.