# EDGAR Filing Document

**Accession Number:** 0001438472
**File Stem:** 0001628280-25-040172
**Filing Date:** 2025-8
**Character Count:** 50178
**Document Hash:** f7723c5ade97d3538f7a85a36a9954ce
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001628280-25-040172.hdr.sgml**: 20250813

**ACCESSION NUMBER**: 0001628280-25-040172

**CONFORMED SUBMISSION TYPE**: S-8

**PUBLIC DOCUMENT COUNT**: 15

**FILED AS OF DATE**: 20250813

**EFFECTIVENESS DATE**: 20250813

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** MIAMI INTERNATIONAL HOLDINGS, INC.
- **CENTRAL INDEX KEY:** 0001438472
- **STANDARD INDUSTRIAL CLASSIFICATION:** SECURITY BROKERS, DEALERS & FLOTATION COMPANIES [6211]
- **ORGANIZATION NAME:** 09 Crypto Assets
- **EIN:** 261482385
- **STATE OF INCORPORATION:** DE

**FILING VALUES:**
- **FORM TYPE:** S-8
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 333-289581
- **FILM NUMBER:** 251212574

**BUSINESS ADDRESS:**
- **STREET 1:** 7 ROSZEL ROAD
- **STREET 2:** FIFTH FLOOR, SUITE 1-A
- **CITY:** PRINCETON
- **STATE:** NJ
- **ZIP:** 08540
- **BUSINESS PHONE:** 609-897-7300

**MAIL ADDRESS:**
- **STREET 1:** 7 ROSZEL ROAD
- **STREET 2:** FIFTH FLOOR, SUITE 1-A
- **CITY:** PRINCETON
- **STATE:** NJ
- **ZIP:** 08540

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** MIAMI INTERNATIONAL HOLDINGS INC
- **DATE OF NAME CHANGE:** 20080624

As filed with the Securities and Exchange Commission on August 13, 2025

**Registration No. 333-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;** 

**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**Washington, D.C. 20549** 

**FORM S-8**

**REGISTRATION STATEMENT**

**UNDER**

**THE SECURITIES ACT OF 1933**

**MIAMI INTERNATIONAL HOLDINGS, INC.**

(Exact name of registrant as specified in its charter)

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| | |
|:---|:---|
| **Delaware** | **26-1482385** |
| (State or other jurisdiction of<br>incorporation or organization) | (I.R.S. Employer<br>Identification No.) |
| **7 Roszel Road, Suite 1A**<br>**Princeton, New Jersey** <br>(Address of Principal Executive Offices) | **08540**<br>(Zip Code) |

---

**2008 Stock Incentive Plan**

**2008 Stock Incentive Plan for Non-Employee Directors and Members of the Board of Advisors**

**2013 Stock Option and Incentive Plan for Employees and Consultants**

**2013 Stock Option and Incentive Plan for Non-Employee Directors, Committee Members and Members of the Board of Advisors**

**2021 Stock Option and Incentive Plan for Employees and Consultants**

**Restricted Stock Awards Outside of Plan**

**2022 Equity Incentive Plan**

(Full title of the plan)

**Thomas P. Gallagher**

**Chairman and Chief Executive Officer**

**Miami International Holdings, Inc.**

**7 Roszel Road, Suite 1A**

**Princeton, New Jersey 08540**

**(609) 897-7300**

(Name, address and telephone number, including area code, of agent for service)

Copy to:

---

| | | |
|:---|:---|:---|
| **Herbert F. Kozlov, Esq.**<br>**Danielle Carbone, Esq.**<br>**Reed Smith LLP**<br>**599 Lexington Avenue**<br>**New York, New York 10022**<br>**(212) 521-5400** | **Barbara Comly, Esq.**<br>**Executive Vice President, General**<br>**Counsel and Corporate Secretary**<br>**Miami International Holdings, Inc.**<br>**7 Roszel Road, Suite 1A**<br>**Princeton, New Jersey 08540**<br>**(609) 897-7300** | **Jeffrey G. Aromatorio, Esq.**<br>**Reed Smith LLP**<br>**225 Fifth Avenue**<br>**Pittsburgh, Pennsylvania 15222**<br> **(412) 288-3364** |

---

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company" and "emerging growth company" in Rule 12b-2 of the Exchange Act.

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| | | | |
|:---|:---|:---|:---|
| Large Accelerated Filer | ☐ | Accelerated Filer | ☐ |
| Non-Accelerated Filer | ☒ | Smaller reporting company | ☐ |
| | | Emerging growth company | 🗷 |

---

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

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**PART I**

**INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS**

Information required by Part I to be contained in the Section 10(a) prospectus is omitted from this Registration Statement in accordance with Rule 428 under the Securities Act of 1933, as amended (the "Securities Act"), and the Note to Part I of Form S-8. The documents containing information specified in this Part I will be separately provided to the participants in the equity compensation plans covered by this Registration Statement, as specified by Rule 428(b)(1) under the Securities Act.

**PART II**

**INFORMATION REQUIRED IN THE REGISTRATION STATEMENT**

**ITEM 3.**&nbsp;&nbsp;&nbsp;&nbsp;**INCORPORATION OF DOCUMENTS BY REFERENCE**

The following documents filed with the Securities and Exchange Commission (the "Commission") by Miami International Holdings, Inc. (the "Registrant") are incorporated herein by reference.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(1)The Registrant's Registration Statement on Form S-1 (File No. 333-288767), filed with the SEC on July 18, 2025, as amended on August 4, 2025, which contains audited financial statements for the Registrant's latest fiscal year for which such statements have been filed;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(2)The Registrant's prospectus to be filed by the Registrant with the SEC pursuant to Rule 424(b) under the Securities Act, relating to the Registrant's Registration Statement on Form S-1 (File No. 333-288767), filed with the SEC on July 18, 2025, as amended on August 4, 2025; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(3)The description of the Registrant's Common Stock which is contained in a registration statement on Form 8-A filed on August 13, 2025 (File No. 001-42805) under the Exchange Act of 1934, as amended (the "Exchange Act"), including any amendment or report filed for the purpose of updating such description.

All documents subsequently filed by the Registrant pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing of a post-effective amendment which indicates that all securities offered have been sold, or which deregisters all securities then remaining unsold, shall be deemed to be incorporated by reference herein and to be a part hereof from the date of filing of such documents.

Any statement contained in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this Registration Statement to the extent that a statement contained herein, or in any other subsequently filed document which also is incorporated or deemed to be incorporated by reference herein, modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement.

Notwithstanding the foregoing, unless specifically stated to the contrary, none of the information disclosed by the Registrant under Items 2.02 or 7.01 of any Current Report on Form 8-K, including the related exhibits under Item 9.01, that the Registrant may from time to time furnish to the Commission will be incorporated by reference into, or otherwise included in, this Registration Statement.

**ITEM 4.**&nbsp;&nbsp;&nbsp;&nbsp;**DESCRIPTION OF SECURITIES**

Not applicable.

**ITEM 5.**&nbsp;&nbsp;&nbsp;&nbsp;**INTEREST OF NAMED EXPERTS AND COUNSEL**

Not applicable.

**ITEM 6.**&nbsp;&nbsp;&nbsp;&nbsp;**INDEMNIFICATION OF DIRECTORS AND OFFICERS**

*Limitation of Directors' and Officers' Liability and Indemnification*

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As permitted by Section 102(b)(7) of the Delaware General Corporation Law (the "DGCL"), our amended and restated certificate of incorporation includes a provision that eliminates the personal liability of our directors for monetary damages for any breach of their fiduciary duties as directors, to the fullest extent permitted by the DGCL.

Section 145(a) of the DGCL provides that a corporation shall have the power to indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending, or completed action, suit, or proceeding, whether civil, criminal, administrative, or investigative (other than an action by or in the right of the corporation) by reason of the fact that the person is or was a director, officer, employee, or agent of the corporation, or is or was serving at the request of the corporation as a director, officer, employee, or agent of another corporation, partnership, joint venture, trust, or other enterprise, against expenses (including attorneys' fees), judgments, fines and amounts paid in settlement actually and reasonably incurred by them in connection with such action, suit, or proceeding if the person acted in good faith and in a manner the person reasonably believed to be in or not opposed to the best interest of the corporation, and, with respect to any criminal action or proceeding, had no reasonable cause to believe their conduct was unlawful. The termination of any action, suit, or proceeding by judgment, order, settlement, conviction, or upon a plea of nolo contendere or its equivalent shall not, of itself, create a presumption that the person did not act in good faith and in a manner which the person reasonably believed to be in or not opposed to the best interests of the corporation, and, with respect to any criminal action or proceeding, had reasonable cause to believe that their conduct was unlawful.

Section 145(b) of the DGCL provides that a corporation shall have the power to indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending, or completed action or suit by or in the right of the corporation to procure a judgment in its favor by reason of the fact that the person is or was a director, officer, employee, or agent of the corporation, or is or was serving at the request of the corporation as a director, officer, employee, or agent of another corporation, partnership, joint venture, trust, or other enterprise against expenses (including attorneys' fees) actually and reasonably incurred by them in connection with the defense or settlement of such action or suit if the person acted in good faith and in a manner the person reasonably believed to be in or not opposed to the best interests of the corporation and except that no indemnification shall be made with respect to any claim, issue, or matter as to which such person shall have been adjudged to be liable to the corporation unless and only to the extent that the Court of Chancery or the court in which such action or suit was brought shall determine upon application that, despite the adjudication of liability but in view of all the circumstances of the case, such person is fairly and reasonably entitled to indemnity for such expenses which the Court of Chancery or such other court shall deem proper.

We have entered into indemnification agreements with our executive officers and directors. These indemnification agreements will provide broader indemnity rights than those provided under the DGCL and our amended and restated certificate of incorporation. These indemnification agreements are not intended to deny or otherwise limit third-party or derivative suits against us or our directors or officers, but to the extent a director or officer were entitled to indemnity or contribution under the indemnification agreement, the financial burden of a third-party suit would be borne by us, and we would not benefit from derivative recoveries against the director or officer. Such recoveries would accrue to our benefit but would be offset by our obligations to the director or officer under the indemnification agreement.

We maintain directors' and officers' liability insurance for the benefit of our directors and executive officers.

**ITEM 7.**&nbsp;&nbsp;&nbsp;&nbsp;**EXEMPTION FROM REGISTRATION CLAIMED**

Not applicable.

------

**ITEM 8.**&nbsp;&nbsp;&nbsp;&nbsp;**EXHIBITS**

The following exhibits are hereby filed as part of this Registration Statement:

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| | |
|:---|:---|
| **Exhibit Number** | **Exhibit Description** |
| <u>4.1</u> | <u>[Amended and Restated Certificate of Incorporation, as currently in effect (incorporated herein by reference to Exhibit 3.1 to the Registrant's Registration Statement on Form S-1 (File No. 001-288767), filed with the SEC on July 18, 2025).](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit31-sx1.htm)</u> |
| <u>4.2</u> | <u>[Amended and Restated By-Laws, as currently in effect (incorporated herein by reference to Exhibit 3.2 to the Registrant's Registration Statement on Form S-1 (File No. 001-288767), filed with the SEC on July 18, 2025).](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit32-sx1.htm)</u> |
| <u>5.1</u> | <u>[Opinion of Reed Smith LLP (filed herewith).](exhibit51-sx8.htm)</u> |
| <u>23.1</u> | <u>[Consent of Independent Registered Public Accounting Firm (filed herewith).](exhibit231-sx8.htm)</u> |
| <u>23.2</u> | <u>[Consent of Reed Smith LLP (reference is made to Exhibit 5.1).](exhibit51-sx8.htm)</u> |
| <u>24.1</u> | <u>[Power of Attorney (reference is made to the signature page hereto).](#i470e84c9e28d411683e7b1696fe38101_34)</u> |
| <u>99.1</u> | <u>[Miami International Holdings, Inc. 2008 Stock Incentive Plan, as amended (incorporated herein by reference to Exhibit 10.1 to the Registrant's Registration Statement on Form S-1 (File No. 333-288767), filed with the SEC on July 18, 2025).](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit101-sx1.htm)</u> |
| <u>99.2</u> | <u>[Miami International Holdings, Inc. 2008 Stock Incentive Plan for Non-Employee Directors and Members of the Board of Advisors, as amended](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit102-sx1.htm)</u> <u>[(incorporated herein by reference to Exhibit 10.2 to the Registrant's Registration Statement on Form S-1 (File No. 333-288767), filed with the SEC on July 18, 2025).](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit102-sx1.htm)</u> |
| <u>99.3</u> | [F](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit103-sx1.htm)<u>[orm of Miami International Holdings, Inc. Stock Option Agreement \[for Employees\] pursuant to 2008 Stock Incentive Plan, as amended](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit103-sx1.htm)</u> <u>[(incorporated herein by reference to Exhibit 10.3 to the Registrant's Registration Statement on Form S-1 (File No. 333-288767), filed with the SEC on July 18, 2025).](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit103-sx1.htm)</u> |
| <u>99.4</u> | <u>[Form of Miami International Holdings, Inc. Non-Qualified Stock Option Agreement \[for Non-Employee Directors\] pursuant to 2008 Stock Incentive Plan for Non-Employee Directors and Members of the Board of Advisors, as amended](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit104-sx1.htm)</u> <u>[(incorporated herein by reference to Exhibit 10.4 to the Registrant's Registration Statement on Form S-1 (File No. 333-288767), filed with the SEC on July 18, 2025).](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit104-sx1.htm)</u> |
| <u>99.5</u> | <u>[Miami International Holdings, Inc. 2013 Stock Option and Incentive Plan for Employees and Consultants, as amended (incorporated herein by reference to Exhibit 10.5 to the Registrant's Registration Statement on Form S-1 (File No. 333-288767), filed with the SEC on July 18, 2025).](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit105-sx1.htm)</u> |
| <u>99.6</u> | <u>[Miami International Holdings, Inc. 2013 Stock Option and Incentive Plan for Non-Employee Directors, Committee Members and Members of the Board of Advisors, as amended](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit106-sx1.htm)</u> <u>[(incorporated herein by reference to Exhibit 10.6 to the Registrant's Registration Statement on Form S-1 (File No. 333-288767), filed with the SEC on July 18, 2025)](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit106-sx1.htm)</u><u>.</u> |
| <u>99.7</u> | <u>[Form of Miami International Holdings, Inc. Notice of Stock Option Grant and Stock Option Award Agreement pursuant to 2013 Stock Option and Incentive Plan for Employees and Consultants, as amended](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit107-sx1a.htm)</u> <u>[(incorporated herein by reference to Exhibit 10.7 to the Registrant's Registration Statement on Form S-1 (File No. 333-288767), filed with the SEC on July 18, 2025).](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit107-sx1a.htm)</u> |
| <u>99.8</u> | <u>[Form of Miami International Holdings, Inc. Restricted Stock Award Agreement pursuant to 2013 Stock Option and Incentive Plan for Employees and Consultants, as amended](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit108-sx1.htm)</u> <u>[(incorporated herein by reference to Exhibit 10.8 to the Registrant's Registration Statement on Form S-1 (File No. 333-288767), filed with the SEC on July 18, 2025).](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit108-sx1.htm)</u> |
| <u>99.9</u> | <u>[Form of Miami International Holdings, Inc. Notice of Stock Option Grant and Stock Option Award Agreement pursuant to 2013 Stock Option and Incentive Plan for Non-Employee Directors, Committee Members and Members of the Board of Advisors, as amended](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit109-sx1.htm)</u> <u>[(incorporated herein by reference to Exhibit 10.9 to the Registrant's Registration Statement on Form S-1 (File No. 333-288767), filed with the SEC on July 18, 2025).](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit109-sx1.htm)</u> |

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| | |
|:---|:---|
| <u>99.10</u> | <u>[Miami International Holdings, Inc. 2021 Stock Option and Incentive Plan for Employees and Consultants](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit1010-sx1.htm)</u> <u>[(incorporated herein by reference to Exhibit 10.10 to the Registrant's Registration Statement on Form S-1 (File No. 333-288767), filed with the SEC on July 18, 2025).](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit1010-sx1.htm)</u> |
| <u>99.11</u> | <u>[Form of Miami International Holdings, Inc. Notice of Stock Option Grant and Stock Option Award Agreement pursuant to 2021 Stock Option and Incentive Plan for Employees and Consultants](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit1011-sx1.htm)</u> <u>[(incorporated herein by reference to Exhibit 10.11 to the Registrant's Registration Statement on Form S-1 (File No. 333-288767), filed with the SEC on July 18, 2025).](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit1011-sx1.htm)</u> |
| <u>99.12</u> | <u>[Form of Miami International Holdings, Inc. Restricted Stock Award Agreement pursuant to 2021 Stock Option and Incentive Plan for Employees and Consultants](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit1012-sx1.htm)</u> <u>[(incorporated herein by reference to Exhibit 10.12 to the Registrant's Registration Statement on Form S-1 (File No. 333-288767), filed with the SEC on July 18, 2025).](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit1012-sx1.htm)</u> |
| <u>99.13</u> | <u>[Omnibus Amendment to Stock Incentive Plans of Miami International Holdings, Inc.](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit1013-sx1.htm)</u> <u>[(incorporated herein by reference to Exhibit 10.13 to the Registrant's Registration Statement on Form S-1 (File No. 333-288767), filed with the SEC on July 18, 2025).](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit1013-sx1.htm)</u> |
| <u>99.14</u> | <u>[Miami International Holdings, Inc. 2022 Equity Incentive Plan](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit1014-sx1.htm)</u> <u>[(incorporated herein by reference to Exhibit 10.14 to the Registrant's Registration Statement on Form S-1 (File No. 333-288767), filed with the SEC on July 18, 2025).](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit1014-sx1.htm)</u> |
| <u>99.15</u> | <u>[Form of Notice of Stock Option Grant and Stock Option Award Agreement pursuant to the Miami International Holdings, Inc. 2022 Equity Incentive Plan](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit1015-sx1.htm)</u> <u>[(incorporated herein by reference to Exhibit 10.15 to the Registrant's Registration Statement on Form S-1 (File No. 333-288767), filed with the SEC on July 18, 2025).](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit1015-sx1.htm)</u> |
| <u>99.16</u> | <u>[Form of Restricted Stock Award Agreement pursuant to the Miami International Holdings, Inc. 2022 Equity Incentive Plan](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit1016-sx1.htm)</u> <u>[(incorporated herein by reference to Exhibit 10.16 to the Registrant's Registration Statement on Form S-1 (File No. 333-288767), filed with the SEC on July 18, 2025).](https://www.sec.gov/Archives/edgar/data/1438472/000162828025035343/exhibit1016-sx1.htm)</u> |
| <u>107</u> | <u>[Filing Fee Table (filed herewith).](miaxexfilingfees81325.htm)</u> |

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**ITEM 9.**&nbsp;&nbsp;&nbsp;&nbsp;**UNDERTAKINGS**

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a)*Rule 415 offering.*

The undersigned Registrant hereby undertakes:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1.To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(i)To include any prospectus required by Section 10(a)(3) of the Securities Act;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(ii)To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the SEC pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than 20% change in the maximum aggregate offering price set forth in the "Calculation of Registration Fee" table in the effective registration statement.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(iii)To include any material information with respect to the plan of distribution not previously disclosed in the Registration Statement or any material change to such information in the registration statement;

*Provided however*, that paragraphs (a)(1)(i) and (a)(1)(ii) of this section do not apply if the registration statement is on Form S-8 and the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the SEC by the Registrant pursuant to

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section 13 or section 15(d) of the Exchange Act that are incorporated by reference in the registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is part of the registration statement.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2.That, for the purpose of determining any liability under the Securities Act, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3.To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b)The undersigned Registrant hereby undertakes that, for purposes of determining any liability under the Securities Act, each filing of the registrant's annual report pursuant to section 13(a) or section 15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan's annual report pursuant to section 15(d) of the Exchange Act) that is incorporated by reference in the Registration Statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c)Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling persons of the Registrant pursuant to the foregoing provisions, or otherwise, the Registrant has been advised that in the opinion of the SEC such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the Registrant of expenses incurred or paid by a director, officer or controlling person of the Registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the Registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

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**SIGNATURES**

Pursuant to the requirements of the Securities Act, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in Princeton, State of New Jersey on August 13, 2025.

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| | |
|:---|:---|
| **MIAMI INTERNATIONAL HOLDINGS, INC.** | **MIAMI INTERNATIONAL HOLDINGS, INC.** |
| By: | /s/ Thomas P. Gallagher |
|  | Thomas P. Gallagher |
|  | Chairman and Chief Executive Officer |

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**POWER OF ATTORNEY**

Each person whose signature appears below constitutes and appoints Thomas P. Gallagher and Barbara J. Comly, and each of them acting individually and without the other, as his or her true and lawful attorneys-in-fact and agents, with full power of substitution and re-substitution, for him or her and in his or her name, place, and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments, exhibits thereto and other documents in connection therewith) to this Registration Statement, and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or either of them individually, or their or his substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

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Pursuant to the requirements of the Securities Act, this Registration Statement has been signed below by the following persons in the capacities and on the dates indicated.

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| | | |
|:---|:---|:---|
| **Signature** | **Title** | **Date** |
| /s/ Thomas P. Gallagher | Chairman and Chief Executive Officer <br>(*Principal Executive Officer*) | August 13, 2025 |
| Thomas P. Gallagher | Chairman and Chief Executive Officer <br>(*Principal Executive Officer*) | August 13, 2025 |
| /s/ Lance Emmons | Executive Vice President and Chief Financial Officer <br>(*Principal Financial and Accounting Officer*) | August 13, 2025 |
| Lance Emmons | Executive Vice President and Chief Financial Officer <br>(*Principal Financial and Accounting Officer*) | August 13, 2025 |
| /s/ Talal Jassim Al-Bahar | Director | August 13, 2025 |
| Talal Jassim Al-Bahar | Director | August 13, 2025 |
| /s/ John Beckelman | Director | August 13, 2025 |
| John Beckelman | Director | August 13, 2025 |
| /s/ Lee Becker | Director | August 13, 2025 |
| Lee Becker | Director | August 13, 2025 |
| /s/ David Brown | Director | August 13, 2025 |
| David Brown | Director | August 13, 2025 |
| /s/ Kurt M. Eckert | Director | August 13, 2025 |
| Kurt M. Eckert | Director | August 13, 2025 |
| /s/ Kenneth W. Lozier | Director | August 13, 2025 |
| Kenneth W. Lozier | Director | August 13, 2025 |
| /s/ Mark I. Massad | Director | August 13, 2025 |
| Mark I. Massad | Director | August 13, 2025 |
| /s/ Lisa Moore | Director | August 13, 2025 |
| Lisa Moore | Director | August 13, 2025 |
| /s/ Jamil Nazarali | Director | August 13, 2025 |
| Jamil Nazarali | Director | August 13, 2025 |
| /s/ Mark F. Raymond | Director | August 13, 2025 |
| Mark F. Raymond | Director | August 13, 2025 |
| /s/ Cynthia Schwarzkopf | Director | August 13, 2025 |
| Cynthia Schwarzkopf | Director | August 13, 2025 |
| /s/ Murray Stahl | Director | August 13, 2025 |
| Murray Stahl | Director | August 13, 2025 |
| /s/ Paul V. Stahlin | Director | August 13, 2025 |
| Paul V. Stahlin | Director | August 13, 2025 |
| /s/ J. Gray Teekell | Director | August 13, 2025 |
| J. Gray Teekell | Director | August 13, 2025 |

---

## Ex-Filing

?xml version='1.0' encoding='ASCII'? EX-FILING FEES

---

| |
|:---|
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Calculation of Filing Fee Tables**  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **S-8**  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **MIAMI INTERNATIONAL HOLDINGS, INC.**  |

---

---

| | | | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|:---|:---|
| | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Security Type**  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Security Class Title**  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Fee Calculation Rule**  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Amount Registered**  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Proposed Maximum Offering Price Per Unit**  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Maximum Aggregate Offering Price**  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Fee Rate**  | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Amount of Registration Fee**  |
| 1 | Equity | Common stock, $0.001 par value per share | Other | 11130534 | $23.00 | $256002282.00 | 0.0001531 | $39193.95 |
| 2 | Equity | Common stock, $0.001 par value per share | Other | 7499594 | $21.25 | $159366372.50 | 0.0001531 | $24398.99 |
| 3 | Equity | Common stock, $0.001 par value per share | Other | 651250 | $12.00 | $7815000.00 | 0.0001531 | $1196.48 |
| 4 | Equity | Common stock, $0.001 par value per share | Other | 25000 | $12.00 | $300000.00 | 0.0001531 | $45.93 |
| 5 | Equity | Common stock, $0.001 par value per share | Other | 8275467 | $12.79 | $105843222.93 | 0.0001531 | $16204.60 |
| 6 | Equity | Common stock, $0.001 par value per share | Other | 835000 | $23.00 | $19205000.00 | 0.0001531 | $2940.29 |
| 7 | Equity | Common stock, $0.001 par value per share | Other | 3172976 | $13.34 | $42327499.84 | 0.0001531 | $6480.34 |
| 8 | Equity | Common stock, $0.001 par value per share | Other | 2837095 | $17.70 | $50216581.50 | 0.0001531 | $7688.16 |
| 9 | Equity | Common stock, $0.001 par value per share | Other | 575287 | $23.00 | $13231601.00 | 0.0001531 | $2025.76 |
| Total Offering Amounts: | Total Offering Amounts: | Total Offering Amounts: | Total Offering Amounts: | Total Offering Amounts: |  | $654307559.77  |  | $100174.50  |
| Total Fee Offsets:  | Total Fee Offsets:  | Total Fee Offsets:  | Total Fee Offsets:  | Total Fee Offsets:  |  |  |  | $0.00  |
| Net Fee Due:  | Net Fee Due:  | Net Fee Due:  | Net Fee Due:  | Net Fee Due:  |  |  |  | $100174.50  |

---

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Offering Note** <br>

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <sup>1</sup> 1a. Pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the "Securities Act"), this registration statement shall also cover any additional shares of the Registrant's Common Stock that become issuable under the 2008 Stock Incentive Plan ("2008 Employee Plan"), 2008 Stock Incentive Plan for Non-Employee Directors and Members of the Board of Advisors ("2008 Director Plan"), 2013 Stock Option and Incentive Plan for Employees and Consultants ("2013 Employee Plan"), 2013 Stock Option and Incentive Plan for Non-Employee Directors, Committee Members and Members of the Board of Advisors ("2013 Director Plan"), 2021 Stock Option and Incentive Plan for Employees and Consultants ("2021 Plan"), Restricted Stock Awards Outside of Plan ("Restricted Stock Awards Outside of Plan"), and 2022 Equity Incentive Plan ("2022 Plan") by reason of any stock dividend, stock split, recapitalization or similar transaction effected without the Registrant's receipt of consideration which would increase the number of outstanding shares of common stock. 1b. Represents shares of Common Stock reserved for issuance under the Registrant's 2022 Plan and outstanding restricted stock awards under the Registrant's 2022 Plan. The number of shares of Common Stock reserved and available for issuance under the 2022 Plan automatically increases on January 1 of each year, beginning January 1, 2023 and continuing through and including January 1, 2032, by 5% of the total number of shares of common stock outstanding on December 31 of the immediately preceding calendar year, or a lesser number of shares determined by the administrator prior to the applicable January 1. Such additional shares have not been included in this Registration Statement and will be registered at such time as each respective increase in shares reserved and available for issuance under the 2022 Plan becomes effective. 1c. Estimated solely for purposes of calculating the amount of the registration fee, pursuant to Rule 457(h) under the Securities Act. The proposed maximum offering price per share and the maximum aggregate offering price are based on the initial public offering price of the Common Stock of $23.00 per share of Common Stock, as set forth in the Registrant's Registration Statement on Form S-1 (File No. 333-288767), as amended (the "S-1 Registration Statement").

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <sup>2</sup> See note 1a. 2a. Represents shares of Common Stock reserved for issuance upon the exercise of outstanding options granted under the Registrant's 2022 Plan. 2b. Estimated solely for the purpose of calculating the registration fee pursuant to Rule 457(h) under the Securities Act, and based upon a price of $21.25 per share, which is the weighted-average exercise price for options outstanding under the 2022 Plan.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <sup>3</sup> See note 1a. 3a. Represents shares of Common Stock reserved for issuance upon the exercise of outstanding options granted under the Registrant's 2008 Employee Plan. 3b. Estimated solely for the purpose of calculating the registration fee pursuant to Rule 457(h) under the Securities Act, and based upon a price of $12 per share, which is the weighted-average exercise price for options outstanding under the 2008 Employee Plan.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <sup>4</sup> See note 1a. 4a. Represents shares of Common Stock reserved for issuance upon the exercise of outstanding options granted under the Registrant's 2008 Director Plan. 4b. Estimated solely for the purpose of calculating the registration fee pursuant to Rule 457(h) under the Securities Act, and based upon a price of $12 per share, which is the weighted-average exercise price for options outstanding under the 2008 Director Plan.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <sup>5</sup> See note 1a. 5a. Represents shares of Common Stock reserved for issuance upon the exercise of outstanding options granted under the Registrant's 2013 Employee Plan. 5b. Estimated solely for the purpose of calculating the registration fee pursuant to Rule 457(h) under the Securities Act, and based upon a price of $12.79 per share, which is the weighted-average exercise price for options outstanding under the 2013 Employee Plan.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <sup>6</sup> See note 1a. 6a. Represents shares of Common Stock reserved for issuance for outstanding restricted stock awards granted under the Registrant's 2013 Employee Plan. 6b. Estimated solely for purposes of calculating the amount of the registration fee, pursuant to Rule 457(h) under the Securities Act. The proposed maximum offering price per share and the maximum aggregate offering price are based on the initial public offering price of the Common Stock of $23.00 per share of Common Stock, as set forth in the S-1 Registration Statement.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <sup>7</sup> See note 1a. 7a. Represents shares of Common Stock reserved for issuance upon the exercise of outstanding options granted under the Registrant's 2013 Director Plan. 7b. Estimated solely for the purpose of calculating the registration fee pursuant to Rule 457(h) under the Securities Act, and based upon a price of $13.34 per share, which is the weighted-average exercise price for options outstanding under the 2013 Director Plan.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <sup>8</sup> See note 1a. 8a. Represents shares of Common Stock reserved for issuance upon the exercise of outstanding options granted under the Registrant's 2021 Plan. 8b. Estimated solely for the purpose of calculating the registration fee pursuant to Rule 457(h) under the Securities Act, and based upon a price of $17.70 per share, which is the weighted-average exercise price for options outstanding under the 2021 Plan.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <sup>9</sup> See note 1a. 9a. Represents shares of Common Stock reserved for issuance for outstanding restricted stock awards granted under Restricted Stock Awards Outside of Plan. 9b. Estimated solely for purposes of calculating the amount of the registration fee, pursuant to Rule 457(h) under the Securities Act. The proposed maximum offering price per share and the maximum aggregate offering price are based on the initial public offering price of the Common Stock of $23.00 per share of Common Stock, as set forth in the S-1 Registration Statement.

---

| | |
|:---|:---|
| | |
| **Rule 457(p)** | **Rule 457(p)** |
| Fee Offset Claims | N/A |
| Fee Offset Sources | N/A |

---

## Exhibit 5.1

**Exhibit 5.1**

---

| | |
|:---|:---|
| ![image_0a.jpg](image_0a.jpg) | Reed Smith LLP<br>599 Lexington Avenue<br>New York, NY 10022-7650<br>+1 212 521 5400<br>Fax +1 212 521 5450<br>reedsmith.com |

---

August 13, 2025

7 Roszel Road, Suite 1A

Princeton, New Jersey

Ladies and Gentlemen:

We have acted as counsel to Miami International Holdings, Inc., a Delaware corporation (the "**Company**"), in connection with the Registration Statement on Form S-8 (the "**Registration Statement**") filed by the Company with the Securities and Exchange Commission (the "**Commission**") under the Securities Act of 1933, as amended (the "**Securities Act**"), relating to the offer and sale by the Company of up to 35,002,203 shares of common stock, par value $0.001 per share of the Company (the "**Shares**"), including (i) 651,250 Shares reserved for issuance upon the exercise of outstanding options granted under the 2008 Stock Incentive Plan ("**2008 Employee Plan**"), (ii) 25,000 Shares reserved for issuance upon the exercise of outstanding options granted under the 2008 Stock Incentive Plan for Non-Employee Directors and Members of the Board of Advisors ("**2008 Director Plan**"), (iii) 8,275,467 Shares reserved for issuance upon the exercise of outstanding options granted under the 2013 Stock Option and Incentive Plan for Employees and Consultants ("**2013 Employee Plan**"), (iv) 835,000 Shares reserved for issuance for outstanding restricted stock awards granted under the 2013 Plan, (v) 3,172,976 Shares reserved for issuance upon the exercise of outstanding options granted under the 2013 Stock Option and Incentive Plan for Non-Employee Directors, Committee Members and Members of the Board of Advisors ("**2013 Director Plan**"), (vi) 2,837,095 Shares reserved for issuance upon the exercise of outstanding options granted under the 2021 Stock Option and Incentive Plan for Employees and Consultants ("**2021 Plan**"), (vii) 11,130,534 Shares reserved for issuance under the 2022 Equity Incentive Plan ("2022 Plan", and together with the 2008 Employee Plan, 2008 Director Plan, 2013 Employee Plan, 2013 Director Plan, and 2021 Plan, the "**Plans**") and outstanding restricted stock awards under the 2022 Plan, (viii) 7,499,594 Shares reserved for issuance upon the exercise of outstanding options granted under the 2022 Plan, and (ix) 575,287 Shares reserved for issuance for outstanding restricted stock awards granted under agreements dated June 23, 2010, October 18, 2011, November 30, 2011, November 30, 2011, and November 30, 2011 ("**Restricted Stock Awards Outside of Plan**"). This opinion letter is being furnished in accordance with the requirements of Item 601(b)(5) of Regulation S-K under the Securities Act.

We have reviewed originals or copies of the Registration Statement, the Amended and Restated Certificate of Incorporation and Amended and Restated By-Laws of the Company, as amended through the date hereof, and such other corporate records, agreements and documents of the Company, certificates or comparable documents of public officials and officers of the Company and have made such other investigations as we have deemed necessary as a basis for the opinion set forth below.

In rendering the opinion set forth below, we have assumed:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a.the genuineness of all signatures;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;b.the legal capacity of natural persons;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;c.the authenticity of all documents submitted to us as originals;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;d.the conformity to original documents of all documents submitted to us as duplicates or conformed copies;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;e.as to matters of fact, the truthfulness of the representations made in certificates or comparable documents of public officials and officers of the Company;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;f.the board of directors of the Company or a duly constituted and acting committee of such board of directors will have taken all action necessary to set the public offering price of the Shares;

------

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;g.with respect to the issuance of the Shares, the amount of valid consideration paid in respect of such Shares will equal or exceed the par value of such Shares; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;h.that there are no agreements or understandings between or among the Company and any participants in the Plans that would expand, modify or otherwise affect the terms of the Plans or the respective rights or obligations of any participants thereunder.

We have not independently established the validity of the foregoing assumptions.

Based upon the foregoing, and subject to the qualifications, assumptions and limitations stated herein, we are of the opinion that, when the Shares are issued and sold by the Company in the manner contemplated in the Registration Statement against payment therefor in the circumstances contemplated by the Plans or the Restricted Stock Awards Outside of Plan and assuming that the individual issuances, grants or awards under the Plans or under the Restricted Stock Awards Outside of Plan are duly authorized by all necessary corporate action of the Company and duly issued, granted or awarded and exercised and paid for, for consideration at least equal to the par value thereof, in accordance with the requirements of law and the Plans (and the agreements and awards either duly adopted thereunder and in accordance therewith) or Restricted Stock Awards Outside of Plan, the offer and sale of the Shares shall have been duly authorized and, when and to the extent that the Shares are issued in accordance with the foregoing, the Shares will be validly issued, fully paid and nonassessable.

Our opinion is limited to the General Corporation Law of the State of Delaware and we do not express any opinion herein concerning any other law. This opinion letter speaks only as of its date.

We hereby consent to the filing of this opinion letter as Exhibit 5.1 to the Registration Statement and to the use of our name therein. In giving such consent, we do not hereby admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act, and the rules and regulations of the Commission promulgated thereunder.

---

| |
|:---|
| Very truly yours, |
| /s/ Reed Smith LLP |
| REED SMITH LLP |

---

## Exhibit 23.1

**Exhibit 23.1**

**Consent of Independent Registered Public Accounting Firm**

We consent to the use of our report dated March 20, 2025, except for the effects of the reverse stock split described in Note 25 to the consolidated financial statements, as to which the date is July 18, 2025, and the change in the composition of the reportable segments described in Notes 2, 4, 12 and 19 to the consolidated financial statements as to which the date is August 4, 2025, with respect to the consolidated financial statements of Miami International Holdings, Inc., incorporated herein by reference.

/s/ KPMG LLP

New York, New York

August 13, 2025

<br>