MIAX CEO Thomas P. Gallagher Exercises Options and Sells Shares

What Happened

• Thomas P. Gallagher, Chairman & CEO of Miami International Holdings, exercised multiple stock option grants on 2026-09-03 to acquire a total of 89,603 shares at various exercise prices (47,000 @ $12.00; 16,666 @ $12.00; 8,333 @ $12.00; 13,140 @ $15.22; 4,464 @ $22.40) for aggregate exercise cost of roughly $1,163,973. On the same day he sold 47,000 of those shares in the open market for a weighted average price of $42.43, generating proceeds of approximately $1,994,210.
• The filing shows matching derivative “disposition” entries at $0.00 reflecting conversion/exercise of the options into shares.

Key Details

• Transaction date: 2026-09-03; Form 4 filed 2026-09-04 (appears timely).
• Sale price range reported: $42.00–$42.68; weighted average sale price $42.43 (47,000 shares sold for $1,994,210).
• Exercise prices and amounts (acquired): 47,000 @ $12.00 ($564,000); 16,666 @ $12.00 ($199,992); 8,333 @ $12.00 ($99,996); 13,140 @ $15.22 ($199,991); 4,464 @ $22.40 ($99,994). Total shares acquired: 89,603; total exercise cash paid ≈ $1.164M.
• Shares owned after transaction: not stated in the provided filing data.
• Footnotes of note:
  • Transaction(s) executed pursuant to a previously established Rule 10b5-1 trading plan (adopted 12/29/2025).
  • Reporting person has beneficial ownership/control via Gallagher Investments, LLC.
  • Some option grants are fully vested; one incentive stock option shows partial vesting (4,464 vested now; remaining 4,464 vest on 6/16/2027 and another 4,464 on 6/16/2028, subject to continued service).
• The filing discloses multiple trades for the sale executed throughout the day; the weighted average price is reported and the filer offers to provide per-trade details on request.

Context

• This was an option exercise combined with an immediate partial sale: Gallagher exercised a mix of vested options and sold a portion (47,000 shares) in the open market—consistent with a common practice of exercising options and selling some shares to cover taxes or exercise costs (the filing notes the sale occurred under a 10b5-1 plan).
• The presence of a Rule 10b5-1 plan indicates these sales were pre-authorized trades; that typically means the timing was pre-set rather than a discretionary sale based on current company-specific information.
• No suggestion of insider misconduct or noncompliance is indicated by the filing; the report appears timely (filed the next day).