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Miami International (MIAX) director Eric Sites details stock option stakes

(Neutral)
(Neutral)
Form Type
3

Rhea-AI Filing Summary

Miami International Holdings, Inc. director Eric Sites filed an initial ownership report showing fully vested nonqualified stock options linked to the company’s shares. The options cover 9,174 underlying shares at an exercise price of $20.0000, 9,554 shares at $19.8400, 7,500 shares at $25.9800, and 7,500 shares at $16.1400, all expiring on March 26, 2030. A footnote notes that Sites was elected to the Board of Directors on April 24, 2026 and that Horizon Kinetics Asset Management LLC separately reported beneficial ownership of 11,162,809 shares on an amended Schedule 13D.

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Insider Sites Eric
Role Director
Type Security Shares Price Value
holding Nonqualified Stock Option (Right to Buy) -- -- --
holding Nonqualified Stock Option (Right to Buy) -- -- --
holding Nonqualified Stock Option (Right to Buy) -- -- --
holding Nonqualified Stock Option (Right to Buy) -- -- --
Holdings After Transaction: Nonqualified Stock Option (Right to Buy) — 33,728 shares (Direct)
Footnotes (3)
  1. F1. These options are fully vested.
  2. F2. On April 24, 2026, Eric Sites, who serves as a Managing Director of Horizon Kinetics Asset Management LLC (HKAM), was elected to the Board of Directors of the Issuer. Mr. Sites does not exercise investment discretion on behalf of HKAM with respect to the securities of the Issuer.
  3. F3. On April 28, 2026, HKAM filed an amendment to its Schedule 13D wherein it reported beneficial ownership of 11,162,809 shares.
Option exercise price $20.0000 per share Nonqualified stock option, 9,174 underlying shares, expires March 26, 2030
Option exercise price $19.8400 per share Nonqualified stock option, 9,554 underlying shares, expires March 26, 2030
Option exercise price $25.9800 per share Nonqualified stock option, 7,500 underlying shares, expires March 26, 2030
Option exercise price $16.1400 per share Nonqualified stock option, 7,500 underlying shares, expires March 26, 2030
Beneficial ownership 11,162,809 shares Shares reported by Horizon Kinetics Asset Management LLC on amended Schedule 13D
Nonqualified Stock Option financial
"security_title: "Nonqualified Stock Option (Right to Buy)""
Schedule 13D regulatory
"HKAM filed an amendment to its Schedule 13D wherein it reported beneficial ownership"
A Schedule 13D is a legal document that investors file with regulators when they buy a large enough stake in a company to potentially influence its management or decisions. It provides details about the investor’s intention, ownership stake, and plans, helping other investors understand who is gaining control and what their motives might be.
beneficial ownership financial
"reported beneficial ownership of 11,162,809 shares"
Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.
Board of Directors financial
"was elected to the Board of Directors of the Issuer"
The Board of Directors is a group of people chosen by a company's owners to help make big decisions and oversee how the company is run. They act like a team of advisors or managers, making sure the company stays on track and meets its goals. Their choices can influence the company's success and how it grows.
fully vested financial
"These options are fully vested."

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

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FAQ

What did Eric Sites report in his Form 3 for MIAX?

Eric Sites reported fully vested nonqualified stock options tied to Miami International Holdings, Inc. (MIAX) shares. The filing lists four option grants with specific exercise prices, share amounts, and a common expiration date in 2030, giving a clear view of his derivative holdings.

How many MIAX shares are covered by Eric Sites’ stock options?

Eric Sites’ options cover four blocks of underlying MIAX shares: 9,174, 9,554, 7,500, and 7,500 shares. These positions together represent multiple nonqualified stock option grants, each with its own exercise price but sharing the same expiration date in 2030.

What are the exercise prices of Eric Sites’ MIAX stock options?

The Form 3 shows exercise prices of $20.0000, $19.8400, $25.9800, and $16.1400 per share for Eric Sites’ nonqualified stock options. These prices define the cost to acquire underlying Miami International Holdings shares before the options expire in 2030.

When do Eric Sites’ MIAX stock options expire?

All listed nonqualified stock options held by Eric Sites expire on March 26, 2030. This shared expiration date applies across the four option positions, each tied to different exercise prices and underlying share amounts in Miami International Holdings, Inc.

What does the Form 3 disclose about Horizon Kinetics and MIAX?

A footnote states that Horizon Kinetics Asset Management LLC filed an amended Schedule 13D reporting beneficial ownership of 11,162,809 MIAX shares. It also notes Eric Sites serves as a Managing Director there but does not exercise investment discretion for MIAX securities.

When was Eric Sites elected to Miami International’s Board of Directors?

Eric Sites was elected to the Board of Directors of Miami International Holdings, Inc. on April 24, 2026. The Form 3 filing coincides with this appointment and provides an initial statement of his derivative holdings through fully vested nonqualified stock options.
SEC Form 3
FORM 3UNITED 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
OMB APPROVAL
OMB Number:3235-0104
Estimated average burden
hours per response:0.5
1. Name and Address of Reporting Person*
Sites Eric

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

(Street)
NEW YORK NEW YORK 10016

(City)(State)(Zip)

UNITED STATES

(Country)
2. Date of Event Requiring Statement (Month/Day/Year)
04/24/2026
3. Issuer Name and Ticker or Trading Symbol
MIAMI INTERNATIONAL HOLDINGS, INC. [ MIAX ]
3a. Foreign Trading Symbol
5. If Amendment, Date of Original Filed (Month/Day/Year)
4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
XDirector10% Owner
Officer (give title below)Other (specify below)
6. Individual or Joint/Group Filing (Check Applicable Line)
XForm filed by One Reporting Person
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)
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 ExercisableExpiration DateTitleAmount or Number of Shares
Nonqualified Stock Option (Right to Buy)(1)08/01/202103/26/2030Miami International Holdings Inc7,500$16.14D(2)(3)
Nonqualified Stock Option (Right to Buy)(1)07/01/202203/26/2030Miami International Holdings Inc7,500$25.98D(2)(3)
Nonqualified Stock Option (Right to Buy)(1)03/27/202303/26/2030Miami International Holdings Inc9,554$19.84D(2)(3)
Nonqualified Stock Option (Right to Buy)(1)04/01/202403/26/2030Miami International Holdings Inc9,174$20D(2)(3)
Explanation of Responses:
1. These options are fully vested.
2. On April 24, 2026, Eric Sites, who serves as a Managing Director of Horizon Kinetics Asset Management LLC (HKAM), was elected to the Board of Directors of the Issuer. Mr. Sites does not exercise investment discretion on behalf of HKAM with respect to the securities of the Issuer.
3. On April 28, 2026, HKAM filed an amendment to its Schedule 13D wherein it reported beneficial ownership of 11,162,809 shares.
/s/Jay Kesslen, attorney-in-fact04/28/2026
** Signature of Reporting PersonDate
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 5 (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 3: SEC 1473 (03-26)