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Updated Jul 16, 2026 · Last SEC filing 2026-07-14
MIAMI INTERNATIONAL HOLDINGS, INC. (MIAX) has filed 62 SEC Form 4 insider transactions in the last 90 days, with the most recent on 2026-07-14. 5 Form 8-K material event filings were reported by MIAX in the last 90 days. 12 Form 144 notices of proposed sale were filed for MIAX stock. InsiderAlpha tracks every MIAX SEC filing — Form 4, Form 144, and 8-K — in real time, including Rule 10b5-1 plan detection.
| SIC classification | Security Brokers, Dealers & Flotation Companies (SIC 6211) |
|---|---|
| SEC CIK | 0001438472 |
| Form 4 filings (90d) | 62 |
|---|---|
| Form 8-K filings (90d) | 5 |
| Form 144 notices (90d) | 12 |
| Latest Form 4 filing | 2026-07-14 |
| Date | Insider | Role | Transaction | Shares | Price | Value | Filing |
|---|---|---|---|---|---|---|---|
| Gallagher Thomas P. | Chairman & CEO | S — Open-market sale [10b5-1] | 70.0K | $42.52 | $2.98M | SEC | |
| Comly Barbara J. | EVP, GC & Corporate Secretary | S — Open-market sale [10b5-1] | 28.0K | $41.98 | $1.18M | SEC | |
| Comly Barbara J. | EVP, GC & Corporate Secretary | M — Option exercise [10b5-1] | 28.0K | $12.00 | $336K | SEC | |
| Gallagher Thomas P. | Chairman & CEO | M — Option exercise [10b5-1] | 70.0K | $12.00 | $840K | SEC | |
| BROWN DAVID A | Director | F — Tax withholding / forfeiture | 171 | $43.72 | $7K | SEC | |
| Gallagher Thomas P. | Chairman & CEO | S — Open-market sale | 28.2K | $42.27 | $1.19M | SEC | |
| Gallagher Thomas P. | Chairman & CEO | M — Option exercise | 28.2K | $12.00 | $339K | SEC | |
| Jayabalan Harish | EVP, CISO and CRO | M — Option exercise | 2.5K | $12.00 | $30K | SEC | |
| Jayabalan Harish | EVP, CISO and CRO | S — Open-market sale | 20.0K | $42.12 | $842K | SEC | |
| Deitzel Edward | EVP, CRO, CCO MIAX Exchanges | S — Open-market sale | 11.0K | $42.04 | $462K | SEC | |
| Deitzel Edward | EVP, CRO, CCO MIAX Exchanges | M — Option exercise | 3.7K | $12.00 | $44K | SEC | |
| Gallagher Thomas P. | Chairman & CEO | M — Option exercise | 41.8K | $12.00 | $501K | SEC | |
| Jayabalan Harish | EVP, CISO and CRO | M — Option exercise | 834 | $12.00 | $10K | SEC | |
| Jayabalan Harish | EVP, CISO and CRO | M — Option exercise | 16.7K | $12.00 | $200K | SEC | |
| Brown Shelly | EVP, Chief Strategy Officer | S — Open-market sale | 16.0K | $42.13 | $674K | SEC |
All transactions sourced from SEC EDGAR Form 4 filings for MIAMI INTERNATIONAL HOLDINGS, INC. (MIAX). Updated in real time as new filings are submitted to the SEC.
| Insider | Form 4 filings | Total transaction value |
|---|---|---|
| Gallagher Thomas P. | 28 | $26.44M |
| Comly Barbara J. | 18 | $7.85M |
| Jayabalan Harish | 16 | $2.12M |
| Deitzel Edward | 15 | $2.08M |
| Schafer Douglas M. JR | 15 | $9.36M |
Form 144 must be filed before insiders sell restricted or control stock above SEC thresholds. A cluster of Form 144 notices often precedes a wave of insider distribution.
SEC Form 4 transactions are reported with a one-letter code indicating the type of transaction. Common codes you'll see in MIAX insider filings:
| P | Open-market purchase by the insider |
|---|---|
| S | Open-market sale by the insider |
| A | Grant, award, or other acquisition from the issuer |
| M | Exercise or conversion of derivative security (e.g. options) |
| F | Payment of exercise price or tax liability via share withholding |
| G | Bona-fide gift of securities |
| D | Disposition to the issuer (e.g. share buyback participation) |
| J | Other acquisition or disposition |
| X | Exercise of in-the-money or at-the-money derivative security |
| C | Conversion of derivative security |
| V | Transaction voluntarily reported earlier than required |
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