Form 4 for MIAX MIAMI INTERNATIONAL HOLDINGS, INC.
Accepted 2026-09-04 16:35:00 ET · period of report 2026-09-03 · accession 0002080477-26-000018 · SEC index · Original document
Summary rows
Aggregated the way they appear in lists: one row per insider, transaction code and security table.
| X | Filed | Traded | Ticker | Insider | Title | Type | Price | Qty | Owned | ΔOwn | Value |
|---|---|---|---|---|---|---|---|---|---|---|---|
| DTI | 2026-09-04 16:35 | 2026-09-03 | MIAX | Gallagher Thomas P. | COB, CEO, Dir | M - OptEx | $12.00 | +47.0K | 1.47M | +3% | +$564.0K |
| DTI | 2026-09-04 16:35 | 2026-09-03 | MIAX | Gallagher Thomas P. | COB, CEO, Dir | S - Sale+OE | $42.43 | -47.0K | 1.42M | -3% | -$1.99M |
| DMT | 2026-09-04 16:35 | 2026-09-03 | MIAX | Gallagher Thomas P. | COB, CEO, Dir | M - OptEx | $14.08 | +42.6K | 786.5K | +6% | +$600.0K |
| DTI | 2026-09-04 16:35 | 2026-09-03 | MIAX | Gallagher Thomas P. | COB, CEO, Dir | M - OptEx | $0.00 | -47.0K | 188.0K | -20% | $0 |
| DMT | 2026-09-04 16:35 | 2026-09-03 | MIAX | Gallagher Thomas P. | COB, CEO, Dir | M - OptEx | $0.00 | -42.6K | 8,928 | -83% | $0 |
Purchase Sale Sale after option exercise All abbreviations
Every reported transaction
| # | Table | Security | Date | Code | A/D | Shares | Price | Owned after | Own | Exercise / expiry | Underlying | Footnotes |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Common | Common Stock | 2026-09-03 | M | A | 47,000 | $12.00 | 1,470,275 | I By Gallagher Investments, LLC | — | — | (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. |
| 2 | Common | Common Stock | 2026-09-03 | S | D | 47,000 | $42.43 | 1,423,275 | I By Gallagher Investments, LLC | — | — | (F1) This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025. (F3) This transaction was executed in multiple trades throughout the day at prices ranging from $42.00 to $42.68. 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. (F2) Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC. |
| 3 | Common | Common Stock | 2026-09-03 | M | A | 16,666 | $12.00 | 760,605 | D | — | — | |
| 4 | Common | Common Stock | 2026-09-03 | M | A | 8,333 | $12.00 | 768,938 | D | — | — | |
| 5 | Common | Common Stock | 2026-09-03 | M | A | 13,140 | $15.22 | 782,078 | D | — | — | |
| 6 | Common | Common Stock | 2026-09-03 | M | A | 4,464 | $22.40 | 786,542 | D | — | — | |
| 7 | Derivative | Nonqualified Stock Option (Right to Buy) | 2026-09-03 | M | D | 47,000 | $0.00 | 188,000 | I By Gallagher Investments, LLC | $12.00 · — to 2028-05-28 | 47,000 Common Stock | (F1) This transaction was effected pursuant to a previously established Rule 10b5-1 Plan adopted by the Reporting Person on December 29, 2025. (F4) The options are fully vested. (F2) Mr. Gallagher maintains beneficial ownership, including dispositive and voting control, over Gallagher Investments, LLC. |
| 8 | Derivative | Incentive Stock Option (Right to Buy) | 2026-09-03 | M | D | 16,666 | $0.00 | 0 | D | $12.00 · — to 2028-05-28 | 16,666 Common Stock | (F4) The options are fully vested. |
| 9 | Derivative | Incentive Stock Option (Right to Buy) | 2026-09-03 | M | D | 8,333 | $0.00 | 0 | D | $12.00 · — to 2029-07-30 | 8,333 Common Stock | (F4) The options are fully vested. |
| 10 | Derivative | Incentive Stock Option (Right to Buy) | 2026-09-03 | M | D | 13,140 | $0.00 | 0 | D | $15.22 · — to 2031-01-27 | 13,140 Common Stock | (F4) The options are fully vested. |
| 11 | Derivative | Incentive Stock Option (Right to Buy) | 2026-09-03 | M | D | 4,464 | $0.00 | 8,928 | D | $22.40 · — to 2035-06-15 | 4,464 Common Stock | (F5) 4,464 of the shares subject to this incentive stock option are vested. 4,464 shares subject to this incentive stock option will vest on June 16, 2027 and the remaining 4,464 shares subject to this incentive stock option will vest on June 16, 2028, subject to the Reporting Person's continued service to the Issuer or its subsidiaries through the applicable vesting date. |