MIAX

miax-20261029

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): October 29, 2026

Miami International Holdings, Inc.

(Exact name of Registrant as Specified in Its Charter)

Delaware001-4280526-1482385

(State or other jurisdiction

of incorporation) (Commission File Number) (IRS Employer

Identification Number)

7 Roszel Road, Suite 1A

Princeton, New Jersey 08540

(Address of Principal Executive Offices)

Registrant’s Telephone Number, Including Area Code: (609) 897-7300

N/A

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class Trading

Symbol(s) Name of each exchange on which registered

Common stock, $0.001 par value per shareMIAXNew York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

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 13(a) of the Exchange Act.  ☐

Item 2.02 Results of Operations and Financial Condition.

On October 29, 2026 Miami International Holdings, Inc. (the “Company”) reported its financial results for the quarter ended September 30, 2026. The Company’s press release, dated October 29, 2026, is attached as Exhibit 99.1 and is incorporated by reference into this Item 2.02.

The information in this Current Report on Form 8-K, including the information contained in Exhibit 99.1, is being furnished to the Securities and Exchange Commission, and shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934 or otherwise subject to the liabilities of that section, and shall not be deemed to be incorporated by reference into any filing under the Securities Act of 1933 or the Securities Exchange Act of 1934, except as shall be expressly set forth by a specific reference in such filing.

In addition to filings with the Securities and Exchange Commission, the Company uses its Investor Relations website as a means of disclosing material non-public information and for complying with its disclosure obligations under Regulation FD.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.Description

99.1

Press release, dated October 29, 2026

104Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Date: October 29, 2026

Miami International Holdings, Inc.

By: /s/ Thomas P. Gallagher_______ Thomas P. Gallagher

Chairman and Chief Executive Officer