Transactions
47
Insider / MIAMI INTERNATIONAL HOLDINGS, INC.
Gallagher Thomas P.
Chairman & CEO at MIAMI INTERNATIONAL HOLDINGS, INC.
- Ticker
- MIAX
- First filing on record
- December 29, 2025
- Latest trade on record
- September 3, 2026
- SEC filings
- EDGAR ↗
Gallagher Thomas P., Chairman & CEO at MIAMI INTERNATIONAL HOLDINGS, INC., has disclosed 47 transactions in MIAX since December 29, 2025: 0 purchases (0 open-market buys) and 15 sales, worth about $47.8M at the reported prices. The latest was filed September 4, 2026, 1 day after the trade; 1 filing was late against the 2-business-day Form 4 deadline.
Open-market buys
0
Sales
15
Avg. disclosure lag
1.5d
Trading in charts
Trade timeline
When does this person trade, how big, and in which direction? Every trade in the last 12 months.
Bought (above the line)Sold (below the line)Other transaction
In the last 12 months Gallagher Thomas P. made no purchases and 15 sales worth $42M, plus 32 other transactions. Dot size is the dollar amount.
Portfolio mix
Which stocks does this person trade most? Tile size is dollars traded, all time on record.
Gallagher Thomas P. has traded 1 stock on record; the largest by dollars is MIAX.
Reporting lag
Does this person report on time? One bar per filing against the Form 4 deadline.
On timeLate
1 of 14 filings on record were reported after the Form 4 deadline (two business days, counted here as 4 calendar days).
What kind of transactions
Most Form 4 rows are pay arriving or tax being withheld, not a decision to buy or sell. Only code P is an open-market purchase and code S an open-market sale. What each code means: Form 4 transaction codes.
| Code | Meaning | Rows | Shares | Value |
|---|---|---|---|---|
| M | Option exercise or conversion | 28 | 1,025,874 | $6.2M |
| S | Open-market sale | 12 | 749,059 | $32.3M |
| A | Grant or award | 3 | 472,637 | — |
| F | Shares withheld for tax | 3 | 221,275 | $9.2M |
| G | Gift | 1 | 2,000 | — |
| Year | Rows | Bought | Sold |
|---|---|---|---|
| 2026 | 46 | 0 | 15 · $41.5M |
| 2025 | 1 | 0 | 0 |
Transactions
| Security | Side | Trade date | Disclosed | Lag | Shares | Price | Value | Flags | Source | Share |
|---|---|---|---|---|---|---|---|---|---|---|
| MIAX | Option / conversion M | September 3, 2026 | September 4, 2026 | 1d | 4,464 | — | — | 10b5-1 planderivative | Form 4 ↗ | |
| MIAX | Option / conversion M | September 3, 2026 | September 4, 2026 | 1d | 13,140 | — | — | 10b5-1 planderivative | Form 4 ↗ | |
| MIAX | Option / conversion M | September 3, 2026 | September 4, 2026 | 1d | 8,333 | — | — | 10b5-1 planderivative | Form 4 ↗ | |
| MIAX | Option / conversion M | September 3, 2026 | September 4, 2026 | 1d | 16,666 | — | — | 10b5-1 planderivative | Form 4 ↗ | |
| MIAX | Option / conversion M | September 3, 2026 | September 4, 2026 | 1d | 47,000 | — | — | 10b5-1 planindirectderivative | Form 4 ↗ | |
| MIAX | Option / conversion M | September 3, 2026 | September 4, 2026 | 1d | 4,464 | $22 | $100K | 10b5-1 plan | Form 4 ↗ | |
| MIAX | Option / conversion M | September 3, 2026 | September 4, 2026 | 1d | 13,140 | $15 | $200K | 10b5-1 plan | Form 4 ↗ | |
| MIAX | Option / conversion M | September 3, 2026 | September 4, 2026 | 1d | 8,333 | $12 | $100K | 10b5-1 plan | Form 4 ↗ | |
| MIAX | Option / conversion M | September 3, 2026 | September 4, 2026 | 1d | 16,666 | $12 | $200K | 10b5-1 plan | Form 4 ↗ | |
| MIAX | Sell S | September 3, 2026 | September 4, 2026 | 1d | 47,000 | $42 | $2.0M | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Option / conversion M | September 3, 2026 | September 4, 2026 | 1d | 47,000 | $12 | $564K | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Sell S | August 19, 2026 | August 20, 2026 | 1d | 149,700 | $41 | $6.2M | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Sell F | August 18, 2026 | August 20, 2026 | 2d | 150,300 | $42 | $6.4M | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Option / conversion M | August 4, 2026 | August 6, 2026 | 2d | 48,334 | — | — | 10b5-1 planindirectderivative | Form 4 ↗ | |
| MIAX | Sell S | August 4, 2026 | August 6, 2026 | 2d | 48,334 | $46 | $2.2M | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Option / conversion M | August 4, 2026 | August 6, 2026 | 2d | 48,334 | $12 | $580K | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Option / conversion M | July 13, 2026 | July 14, 2026 | 1d | 70,000 | — | — | 10b5-1 planindirectderivative | Form 4 ↗ | |
| MIAX | Sell S | July 13, 2026 | July 14, 2026 | 1d | 70,000 | $43 | $3.0M | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Option / conversion M | July 13, 2026 | July 14, 2026 | 1d | 70,000 | $12 | $840K | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Option / conversion M | July 7, 2026 | July 7, 2026 | 0d | 28,228 | — | — | 10b5-1 planindirectderivative | Form 4 ↗ | |
| MIAX | Option / conversion M | July 6, 2026 | July 7, 2026 | 1d | 41,772 | — | — | 10b5-1 planindirectderivative | Form 4 ↗ | |
| MIAX | Sell S | July 7, 2026 | July 7, 2026 | 0d | 28,228 | $42 | $1.2M | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Option / conversion M | July 7, 2026 | July 7, 2026 | 0d | 28,228 | $12 | $339K | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Sell S | July 6, 2026 | July 7, 2026 | 1d | 41,772 | $42 | $1.8M | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Option / conversion M | July 6, 2026 | July 7, 2026 | 1d | 41,772 | $12 | $501K | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Other A | June 16, 2026 | June 18, 2026 | 2d | 237,175 | — | — | derivative | Form 4 ↗ | |
| MIAX | Other A | June 16, 2026 | June 18, 2026 | 2d | 2,485 | — | — | derivative | Form 4 ↗ | |
| MIAX | Other A | June 16, 2026 | June 18, 2026 | 2d | 232,977 | — | — | Form 4 ↗ | ||
| MIAX | Option / conversion M | June 2, 2026 | June 4, 2026 | 2d | 70,000 | — | — | 10b5-1 planindirectderivative | Form 4 ↗ | |
| MIAX | Sell S | June 2, 2026 | June 4, 2026 | 2d | 70,000 | $42 | $3.0M | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Option / conversion M | June 2, 2026 | June 4, 2026 | 2d | 70,000 | $12 | $840K | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Option / conversion M | May 11, 2026 | May 13, 2026 | 2d | 24,999 | — | — | derivative | Form 4 ↗ | |
| MIAX | Option / conversion M | May 11, 2026 | May 13, 2026 | 2d | 24,999 | $12 | $300K | Form 4 ↗ | ||
| MIAX | Option / conversion M | May 5, 2026 | May 7, 2026 | 2d | 15,771 | — | — | 10b5-1 planindirectderivative | Form 4 ↗ | |
| MIAX | Sell S | May 5, 2026 | May 7, 2026 | 2d | 15,771 | $48 | $756K | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Option / conversion M | May 5, 2026 | May 7, 2026 | 2d | 15,771 | $12 | $189K | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Option / conversion M | May 4, 2026 | May 5, 2026 | 1d | 54,229 | — | — | 10b5-1 planindirectderivative | Form 4 ↗ | |
| MIAX | Sell S | May 4, 2026 | May 5, 2026 | 1d | 54,229 | $47 | $2.6M | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Option / conversion M | May 4, 2026 | May 5, 2026 | 1d | 54,229 | $12 | $651K | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Option / conversion M | April 15, 2026 | April 17, 2026 | 2d | 70,001 | — | — | 10b5-1 planindirectderivative | Form 4 ↗ | |
| MIAX | Sell S | April 15, 2026 | April 17, 2026 | 2d | 49,900 | $44 | $2.2M | 10b5-1 plan | Form 4 ↗ | |
| MIAX | Sell S | April 15, 2026 | April 17, 2026 | 2d | 104,124 | $43 | $4.5M | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Sell S | April 15, 2026 | April 17, 2026 | 2d | 70,001 | $43 | $3.0M | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Option / conversion M | April 15, 2026 | April 17, 2026 | 2d | 70,001 | $12 | $840K | 10b5-1 planindirect | Form 4 ↗ | |
| MIAX | Sell F | March 30, 2026 | April 1, 2026 | 2d | 20,875 | $38 | $783K | indirect | Form 4 ↗ | |
| MIAX | Sell F | February 10, 2026 | February 12, 2026 | 2d | 50,100 | $41 | $2.1M | Form 4 ↗ | ||
| MIAX | Other G | December 23, 2025 | December 29, 2025 | 6d | 2,000 | — | — | late | Form 4 ↗ |
Filings
| Filed | Form | Accession | Rows | Status | Source |
|---|---|---|---|---|---|
| September 4, 2026 | Form 4 | 0002080477-26-000018 | 11 | published | EDGAR ↗ |
| August 20, 2026 | Form 4 | 0002080477-26-000016 | 2 | published | EDGAR ↗ |
| August 6, 2026 | Form 4 | 0002080477-26-000014 | 3 | published | EDGAR ↗ |
| July 14, 2026 | Form 4 | 0001628280-26-048149 | 3 | published | EDGAR ↗ |
| July 7, 2026 | Form 4 | 0001628280-26-047530 | 6 | published | EDGAR ↗ |
| June 18, 2026 | Form 4 | 0002080477-26-000012 | 3 | published | EDGAR ↗ |
| June 4, 2026 | Form 4 | 0002080477-26-000010 | 3 | published | EDGAR ↗ |
| May 13, 2026 | Form 4 | 0002080477-26-000008 | 2 | published | EDGAR ↗ |
| May 7, 2026 | Form 4 | 0002080477-26-000006 | 3 | published | EDGAR ↗ |
| May 5, 2026 | Form 4 | 0001628280-26-030147 | 3 | published | EDGAR ↗ |
| April 17, 2026 | Form 4 | 0001628280-26-025753 | 5 | published | EDGAR ↗ |
| April 1, 2026 | Form 4 | 0002080477-26-000004 | 1 | published | EDGAR ↗ |
| February 12, 2026 | Form 4 | 0002080477-26-000002 | 1 | published | EDGAR ↗ |
| December 29, 2025 | Form 4 | 0002080477-25-000012 | 1 | published | EDGAR ↗ |
Other insiders at MIAMI INTERNATIONAL HOLDINGS, INC.
- Brown Shelly EVP, Chief Strategy Officer 40 rows
- Comly Barbara J. EVP, GC & Corporate Secretary 35 rows
- Schafer Douglas M. JR EVP and CIO 34 rows
- Deitzel Edward EVP, CRO, CCO MIAX Exchanges 32 rows
- Jayabalan Harish EVP, CISO and CRO 23 rows
- Eckert Kurt M. Director 18 rows
- STAHL MURRAY Director 13 rows
- Teekell Judson Gray Director 13 rows
- Emmons Lance EVP and CFO 12 rows
- Schwarzkopf Cynthia Director 12 rows
Everyone on file, with contracts and lobbying under the company's name: MIAMI INTERNATIONAL HOLDINGS, INC..
Guides for this page
- What is SEC Form 4? Who files: officers, directors and owners of more than 10% of a class of the company's shares.
- Form 4 transaction codes P = purchase. S = sale. These are the two market trades.
- Insider buying vs insider selling Selling outweighs buying by a wide margin in normal times.
- Rule 10b5-1 trading plans The plan must be set up when the insider has no important non-public information.
- Options and derivatives on Form 4 Table I = shares. Table II = options and other derivatives.
Sources and method
| Source | Filings | Rows | First filed | Newest filed | Read the originals |
|---|---|---|---|---|---|
| SEC EDGAR, Form 4 | 14 | 47 | December 29, 2025 | September 4, 2026 | Form 4 list on EDGAR |
Site built October 27, 2026. Every row in the tables above links to its own filing. To quote a figure, use the Cite button at the top of the page; see how to cite and reuse.
Every row comes from the reporting owner's Form 4 as filed with the SEC (EDGAR ownership XML), read daily. "Value" is shares × the reported price; code P is an open-market purchase, S a sale, M an option exercise, A a grant. The lag is the filing date minus the trade date; Form 4 is due within two business days. Amendments (4/A) are not merged. Details on the methodology page; report an error on corrections.
Not investment advice. Figures are public disclosures shown as filed; they may lag the trade and may be amended later. No recommendation is made or implied.