MIAMI INTERNATIONAL HOLDINGS, INC.·4

Jun 4, 4:37 PM ET

Gallagher Thomas P. 4

4 · MIAMI INTERNATIONAL HOLDINGS, INC. · Filed Jun 4, 2026

Research Summary

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MIAX CEO Thomas P. Gallagher Sells 70,000 Shares After Exercising Options

What Happened
Thomas P. Gallagher, Chairman & CEO of Miami International Holdings, Inc. (MIAX), exercised 70,000 vested stock options at $12.00 per share (cost $840,000) and sold those 70,000 shares in the open market on June 2, 2026 for a weighted average price of $42.36, generating gross proceeds of approximately $2,965,200. The exercise and sale occurred the same day, effectively a cashless exercise followed by an open-market disposition.

Key Details

  • Transaction date: June 2, 2026 (reported on Form 4 filed June 4, 2026).
  • Option exercise: 70,000 shares at $12.00 = $840,000 (options reported as fully vested).
  • Open-market sale: 70,000 shares at weighted avg $42.36 = $2,965,200; trades executed across prices $42.00–$45.73.
  • Net proceeds before fees/taxes: roughly $2.12M (gross sale minus exercise cost).
  • Shares owned after transaction: not specified in this Form 4.
  • Notable footnotes: sale executed pursuant to a Rule 10b5-1 plan adopted Dec 29, 2025; Gallagher maintains beneficial ownership/control over Gallagher Investments, LLC; options fully vested.
  • Filing timeliness: Form 4 filed June 4 for a June 2 transaction (no late-filing indication in the report).

Context
Because the options were exercised and the resulting shares were sold the same day, this is effectively a cashless exercise — the sale converted the option value to cash rather than indicating a new purchase position. Sales under 10b5-1 plans are pre-arranged and are often executed for diversification or liquidity; the filing is factual and does not by itself indicate the insider’s view of the company’s prospects.

Insider Transaction Report

Form 4
Period: 2026-06-02
Gallagher Thomas P.
DirectorChairman & CEO
Transactions
  • Exercise/Conversion

    Common Stock

    [F1][F2]
    2026-06-02$12.00/sh+70,000$840,0001,793,275 total(indirect: By LLC)
  • Sale

    Common Stock

    [F1][F3][F2]
    2026-06-02$42.36/sh70,000$2,965,2001,723,275 total(indirect: By LLC)
  • Exercise/Conversion

    Nonqualified Stock Option (Right to Buy)

    [F1][F4][F2]
    2026-06-0270,000140,000 total(indirect: By LLC)
    Exercise: $12.00Exp: 2026-08-02Common Stock (70,000 underlying)
Footnotes (4)
  • [F1]This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025.
  • [F2]Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC.
  • [F3]This transaction was executed in multiple trades throughout the day at prices ranging from $42.00 to $45.73. The price reported above reflects the weighted average sales price. The Reporting Person hereby undertakes to provide upon request to the Securities and Exchange Commission staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected.
  • [F4]The options are fully vested.
Signature
/s/Alessandra Maria Corona Henriques, Attorney-in-Fact|2026-06-04

Documents

1 file
  • 4
    wk-form4_1780605422.xmlPrimary

    FORM 4