MIAX (NYSE: MIAX) sells 90% of MIAXdx to Robinhood–SIG joint venture

Rhea-AI Filing Summary

Miami International Holdings, Inc. reported that it has closed the previously announced transaction to sell 90% of the issued and outstanding equity of MIAX Derivatives Exchange (MIAXdx), a wholly owned subsidiary, to a joint venture established by Robinhood Markets, Inc. in partnership with Susquehanna International Group. The Company has retained the remaining 10% equity interest in MIAXdx, so it continues to participate in the derivatives exchange while transferring majority ownership to the joint venture.

The transaction was effective as of January 20, 2026, and Miami International Holdings issued a press release on January 21, 2026, providing further details. That press release is included as Exhibit 99.1 to this report.

Insights

Equity market structure and exchanges analyst

Miami International sells 90% of MIAXdx to a Robinhood–Susquehanna JV while keeping a 10% stake.

Miami International Holdings, Inc. has completed the sale of 90% of its MIAX Derivatives Exchange subsidiary to a joint venture formed by Robinhood Markets, Inc. and Susquehanna International Group, with the deal effective on January 20, 2026. MIAXdx was previously wholly owned, so this marks a shift from full control to minority ownership while still maintaining a 10% equity interest.

The filing does not state financial terms, so the economic impact depends on consideration and any ongoing commercial arrangements described outside this excerpt. Strategically, transferring control of MIAXdx to a Robinhood–Susquehanna venture may reshape how the exchange is positioned and used, while Miami International’s retained stake preserves some alignment with the platform’s future performance.

Further detail is contained in the January 21, 2026 press release referenced as Exhibit 99.1, which would outline transaction terms, strategic rationale, and any expected changes to Miami International’s role in the derivatives trading ecosystem.

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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): January 20, 2026

________________________________________

Miami International Holdings, Inc.

(Exact name of Registrant as Specified in Its Charter)

________________________________________

Delaware			001-42805			26-1482385
(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 share			MIAX			New 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 8.01 Other Events.

     On January 21, 2026, Miami International Holdings, Inc. (the “Company”) issued a press release announcing the closing of the previously announced agreement with a joint venture established by Robinhood Markets, Inc. in partnership with Susquehanna International Group to sell 90% of the issued and outstanding equity of MIAX Derivatives Exchange (“MIAXdx”), a wholly owned subsidiary of the Company. The Company has retained 10% of the issued and outstanding equity of MIAXdx. The transaction was effective as of January 20, 2026.

The Company's press release, dated January 21, 2026, is attached as Exhibit 99.1 and is incorporated by reference into this Item 8.01.

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.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.			Description
99.1			Press Release, dated January 21, 2026
104			Cover 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: January 21, 2026

Miami International Holdings, Inc.

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

Chairman and Chief Executive Officer

FAQ

What major transaction did MIAX (Miami International Holdings, Inc.) disclose?

Miami International Holdings, Inc. disclosed that it closed a transaction to sell 90% of the issued and outstanding equity of its wholly owned subsidiary, MIAX Derivatives Exchange (MIAXdx), to a joint venture established by Robinhood Markets, Inc. in partnership with Susquehanna International Group.

How much of MIAX Derivatives Exchange does MIAX retain after the sale?

After the closing of the transaction, Miami International Holdings, Inc. retains 10% of the issued and outstanding equity of MIAX Derivatives Exchange (MIAXdx).

When did the MIAXdx transaction with the Robinhood–Susquehanna joint venture become effective?

The transaction involving the sale of 90% of MIAX Derivatives Exchange to the Robinhood–Susquehanna joint venture became effective as of January 20, 2026.

Which companies are involved in the joint venture that acquired 90% of MIAXdx from MIAX?

The joint venture that acquired 90% of MIAX Derivatives Exchange from Miami International Holdings, Inc. was established by Robinhood Markets, Inc. in partnership with Susquehanna International Group.

Where can investors find more details about MIAX’s sale of MIAXdx?

Additional details are provided in the Company’s press release dated January 21, 2026, which is attached to the report as Exhibit 99.1 and incorporated by reference into Item 8.01.

Does the MIAX 8-K filing state whether the MIAXdx information is filed or furnished?

The report states that the information under Item 8.01, including Exhibit 99.1, is being furnished to the Securities and Exchange Commission and is not deemed to be "filed" for purposes of Section 18 of the Securities Exchange Act of 1934.