Form 4: Gallagher Trades MIAX Stock Under 10b5-1 Plan

Thomas P. Gallagher, Chairman & CEO of Miami International Holdings, Inc. (MIAX), executed a Rule 10b5-1 plan, acquiring 54,229 shares at $12 and disposing of an equal number at $47.26.

Summary

• Thomas P. Gallagher, Chairman & CEO of Miami International Holdings, Inc. (MIAX), reported transactions involving common stock on May 4, 2026.
• These transactions were conducted under a Rule 10b5-1 trading plan established on December 29, 2025.
• Gallagher acquired 54,229 shares of common stock at a price of $12 per share.
• Concurrently, he disposed of 54,229 shares of common stock at a price of $47.26 per share.
• Following these transactions, Gallagher beneficially owns 1,723,275 shares indirectly through Gallagher Investments, LLC.
• Additionally, Gallagher holds 225,771 derivative securities (nonqualified stock options) which are fully vested.

Sentiment

Score: 5

Explanation: StockSavvy.ai views this as a neutral filing. While the transactions show a profit, they are part of a pre-planned strategy and do not indicate new positive or negative developments for the company itself.

Positives

• The transactions were executed under a pre-established Rule 10b5-1 plan, indicating a structured and pre-determined trading strategy.
• Gallagher's options are fully vested, suggesting a long-term commitment and potential for future equity participation.
• The disposal price of $47.26 per share is significantly higher than the acquisition price of $12 per share for the same number of shares, indicating a profitable execution of the plan.

Negatives

• A significant number of shares were disposed of, which could be interpreted as a reduction in direct beneficial ownership by a key executive, although this is mitigated by the Rule 10b5-1 plan and indirect ownership.

Risks

• The filing does not explicitly mention any new or emerging risks. The primary risk associated with such transactions is the potential for negative market perception if the disposal of shares by a key executive is not adequately contextualized by the Rule 10b5-1 plan.

Future Outlook

The filing does not contain forward-looking statements or guidance. The transactions are based on a pre-existing plan.

Management Comments

• The transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025.
• Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC.
• The options are fully vested.

Industry Context

StockSavvy.ai notes that the execution of Rule 10b5-1 plans by corporate insiders is a common practice to diversify holdings or meet financial obligations while adhering to insider trading regulations. The significant difference between the acquisition and disposal prices suggests a favorable market movement or a well-timed plan execution.

Stakeholder Impact

• Shareholders: The disposal of shares by a key executive, even under a 10b5-1 plan, might be scrutinized. However, the plan's existence and the higher disposal price may mitigate negative sentiment.
• Employees: No direct impact mentioned.
• Creditors: No direct impact mentioned.
• Suppliers: No direct impact mentioned.
• Customers: No direct impact mentioned.

Next Steps

• Continued monitoring of Thomas P. Gallagher's beneficial ownership and any future transactions.
• Observation of Miami International Holdings, Inc.'s stock performance and any related company announcements.

Key Dates

Keywords

SEC Form 4, Insider Trading, Rule 10b5-1, Miami International Holdings, MIAX, Thomas P. Gallagher, Stock Options, Beneficial Ownership, Securities Transaction