Miami International Holdings (NYSE: MIAX) holder plans sale of 149,700 shares

Rhea-AI Filing Summary

MIAMI INTERNATIONAL HOLDINGS, INC. (MIAX) received a notice that Gallagher Investments LLC intends to sell up to 149,700 shares of common stock under Rule 144. The proposed sale is to be executed through Morgan Stanley Smith Barney LLC, with the common stock listed on the NYSE.

Gallagher Investments LLC previously executed multiple Rule 10b5-1 plan sales of MIAX common stock over the past three months, each with specified share amounts and aggregate dollar values.

Key Figures

Shares proposed to be sold: 149,700 shares Planned sale date: 08/15/2026 Recent sale on 08/04/2026: 48,334 shares; $2,208,288.63 +4 more

7 metrics

Shares proposed to be sold 149,700 shares Maximum MIAX common shares indicated for sale under Rule 144

Planned sale date 08/15/2026 Date associated with securities to be sold as Restricted Stock Awards

Recent sale on 08/04/2026 48,334 shares; $2,208,288.63 10b5-1 sale of MIAX common stock by Gallagher Investments LLC

Recent sale on 07/13/2026 70,000 shares; $2,976,698.67 10b5-1 sale of MIAX common stock by Gallagher Investments LLC

Recent sale on 07/07/2026 28,228 shares; $1,193,200.38 10b5-1 sale of MIAX common stock by Gallagher Investments LLC

Recent sale on 07/06/2026 41,772 shares; $1,758,292.77 10b5-1 sale of MIAX common stock by Gallagher Investments LLC

Recent sale on 06/02/2026 70,000 shares; $2,964,969.00 10b5-1 sale of MIAX common stock by Gallagher Investments LLC

Key Terms

Rule 144, Restricted Stock Awards, 10b5-1 Sales, Notice of proposed sale

4 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Restricted Stock Awards financial

"Common | 08/15/2026 | Restricted Stock Awards | Issuer"

Restricted stock awards are company shares given to employees or executives that cannot be sold or transferred until certain conditions — like staying with the company for a set time or meeting performance targets — are met, like a gift that is locked in a safe until rules are satisfied. Investors care because these awards tie management’s pay to company performance, can increase the number of shares outstanding when they become tradable (dilution), and may signal expected future selling pressure or commitment to long-term growth.

10b5-1 Sales regulatory

"10b5-1 Sales for GALLAGHER INVESTMENTS LLC 7 Roszel Road"

10b5-1 sales are pre-arranged stock-trading plans that let company insiders automatically buy or sell shares according to a fixed schedule or formula, even if they later learn confidential information. Think of it as setting up an automatic thermostat for trades: it creates a clear, documented path that can protect insiders from insider-trading accusations and gives investors a signal about predictable insider activity—though it can also simply be a way for insiders to diversify or raise cash.

Notice of proposed sale regulatory

"Information is to be given not only as to the person for whose account the securities are to be sold"

FAQ

What is being reported for MIAX in this Form 144 filing?

The filing reports that Gallagher Investments LLC intends to sell up to 149,700 MIAX common shares under Rule 144 through Morgan Stanley Smith Barney LLC, indicating a planned resale of restricted or control securities.

How many MIAX shares does Gallagher Investments LLC plan to sell under Rule 144?

Gallagher Investments LLC plans to sell up to 149,700 shares of MIAX common stock. This amount represents the maximum number of securities indicated in the notice of proposed sale filed under Rule 144.

Which broker is handling the planned MIAX share sale for Gallagher Investments LLC?

The planned sale of MIAX common shares is to be executed through Morgan Stanley Smith Barney LLC Executive Financial Services, located at 1 New York Plaza, as identified in the broker section of the notice.

What prior MIAX stock sales by Gallagher Investments LLC are disclosed in this Form 144?

The notice lists several prior Rule 10b5-1 sales of MIAX common stock over the past three months, each showing the trade date, number of shares sold, and corresponding aggregate dollar amount for those transactions.

Are the MIAX shares in this Form 144 related to restricted stock awards?

Yes. The securities to be sold are described as Common shares acquired as Restricted Stock Awards from the issuer, with the proposed sale date noted as 08/15/2026 in the securities-to-be-sold section.

Does this MIAX Form 144 mention a Rule 10b5-1 trading plan?

Yes. Recent MIAX stock sales by Gallagher Investments LLC are labeled as 10b5-1 Sales, indicating they were executed pursuant to a Rule 10b5-1 trading plan over the prior three-month period.

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

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Available on EDGAR 08/19/2026 - 04:39 PM Accepted by SEC EDGAR 08/19/2026 - 04:39 PM Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0002080477
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	Miami International Holdings, Inc.
SEC File Number	001-42805
Address of Issuer	7 Roszel Road, Suite 1A Princeton NEW JERSEY 08540
Phone	6098977300
Name of Person for Whose Account the Securities are To Be Sold	GALLAGHER INVESTMENTS LLC
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Director
Relationship to Issuer	Officer

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York Plaza 8th Floor New York NY 10004	149700	6273927.00	99230898	08/19/2026	NYSE

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	08/15/2026	Restricted Stock Awards	Issuer			149700	08/15/2026	N/A

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
10b5-1 Sales for GALLAGHER INVESTMENTS LLC 7 Roszel Road, Suite 1A Princeton NJ 08540	Common	08/04/2026	48334	2208288.63
10b5-1 Sales for GALLAGHER INVESTMENTS LLC 7 Roszel Road, Suite 1A Princeton NJ 08540	Common	07/13/2026	70000	2976698.67
10b5-1 Sales for GALLAGHER INVESTMENTS LLC 7 Roszel Road, Suite 1A Princeton NJ 08540	Common	07/07/2026	28228	1193200.38
10b5-1 Sales for GALLAGHER INVESTMENTS LLC 7 Roszel Road, Suite 1A Princeton NJ 08540	Common	07/06/2026	41772	1758292.77
10b5-1 Sales for GALLAGHER INVESTMENTS LLC 7 Roszel Road, Suite 1A Princeton NJ 08540	Common	06/02/2026	70000	2964969.00

144: Remarks and Signature

Remarks
Date of Notice	08/19/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	12/29/2025
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Thomas P. Gallagher
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)