Latest filingSep 04, 2026Most recent Form 4
MIAX
MIAMI INTERNATIONAL HOLDINGS, INC.
NYSEFinancialsSecurity Brokers, Dealers & Flotation Companies
Insider activity for last month from 08/05 to 09/05. Counts use processed Form 4 rows. Purchase and sale metrics use codes P and S; totals remain unknown when any matching value is missing. Rows without a usable transaction date cannot be assigned to a rolling period and are excluded.
Total buying$00 buys
Total selling$1.44B9 sells
Net open-market-$1.44B7 insiders
Open-market mix
Buy vs sell distribution by transaction countInsider activity report
Monthly open-market purchase and sale counts Buys Sells
Transaction codes
By Form 4 transaction code in selected period31transactions
- M · Option exercise · dominant20 · 65%
- S · Open-market sells9 · 29%
- F · Tax withholding2 · 6%
Activity by reported role
A joint filing can contribute to multiple roles58transactions
- Chief executive officer · dominant13 · 22%
- CHAIR13 · 22%
- EVP7 · 12%
- EC6 · 10%
- Director5 · 9%
- GC4 · 7%
- SECY4 · 7%
- CME3 · 5%
- CRO3 · 5%
Distinct insiders active
Reporting-owner CIKs by month · peak Sep 2026 (5)Aug 2026Sep 2026
Reported Holdings After
Separated by insider, security, and ownership typeGallagher Thomas P.Common Stock · Indirect · By Gallagher Investments, LLC
1,423,275Sep 03, 2026
Gallagher Thomas P.Incentive Stock Option (Right to Buy) · Direct
8,928Sep 03, 2026
Gallagher Thomas P.Common Stock · Direct
786,542Sep 03, 2026
Comly Barbara J.Common Stock · Direct
839,564Sep 02, 2026
Schafer Douglas M. JRCommon Stock · Direct
387,414Sep 02, 2026
Schwarzkopf CynthiaCommon Stock · Direct
93,545Aug 17, 2026
Schafer Douglas M. JRNonqualified Stock Option (Right to Buy) · Direct
195,334Sep 02, 2026
Deitzel EdwardCommon Stock · Direct
119,601Sep 03, 2026
These are reported post-transaction holdings, not company-wide ownership percentages. Securities, indirect vehicles, and amendments are kept separate.
Filing activity heatmap
Each cell is one day · intensity = transactions · buys green, sells redAug 05 → Sep 05
LessMore
Top insiders
By absolute net value across the selected period- GP-$8.2M
- SJ-$1.9M
- CJ-$1.8M
- EL-$1.5M
- DE-$464.3k
Filing detail checks
Secondary metrics for the selected periodFiling-only signals
Deterministic matches in the selected period
MIAX transaction history
Filters apply within this company and selected period by default| Ticker | Insider | Role | Type | Shares | Value | Code | Signals | 90d return | Filed | Trans date |
|---|---|---|---|---|---|---|---|---|---|---|
| MIAX | Gallagher Thomas P. | CHAIRCEO | sale10b5-1 | 47.0k | -$199M | S | — | 0.0% | 09/04 | 09/03 |
| MIAX | Comly Barbara J. | EVPGCSECY | sale10b5-1 | 44.4k | -$179M | S | — | 0.0% | 09/04 | 09/02 |
| MIAX | Deitzel Edward | EVPCROCME | sale10b5-1 | 11.0k | -$46.4M | S | — | 0.0% | 09/04 | 09/03 |
| MIAX | Schafer Douglas M. JR | EC | sale10b5-1 | 48.0k | -$194M | S | — | 0.0% | 09/04 | 09/02 |
| MIAX | Teekell Judson Gray | DIR | sale10b5-1 | 3.00k | -$12.2M | S | — | 0.0% | 09/04 | 09/02 |
| MIAX | Teekell Judson Gray | DIR | sale10b5-1 | 5.54k | -$23.0M | S | — | 0.0% | 09/04 | 09/02 |
| MIAX | Gallagher Thomas P. | CHAIRCEO | sale10b5-1 | 149k | -$615M | S | +1.9% | 08/20 | 08/19 | |
| MIAX | Schwarzkopf Cynthia | DIR | sale10b5-1 | 5.00k | -$21.4M | S | +3.7% | 08/19 | 08/17 | |
| MIAX | Emmons Lance | EC | sale10b5-1 | 35.0k | -$149M | S | +3.7% | 08/19 | 08/17 |
MIAMI INTERNATIONAL HOLDINGS, INC. Insider Activity FAQ
SEC Form 4 contextWho recently reported transactions at MIAMI INTERNATIONAL HOLDINGS, INC.?
Gallagher Thomas P., Comly Barbara J., Deitzel Edward, Schafer Douglas M. JR, Teekell Judson Gray, Schwarzkopf Cynthia, Emmons Lance.
When was the latest reported open-market purchase?
No code-P purchase is available for this period.
When was the latest reported open-market sale?
Gallagher Thomas P. reported a sale on Sep 03, 2026 valued at $199M. Read the SEC filing.
What is the recent purchase and sale balance?
Net open-market selling in the selected period was $14,424,830.15. Sales can occur for many non-investment reasons.
Where can I see the original SEC filing?
Every transaction row and latest-activity fact links to its original SEC filing.
What do these Form 4 transaction codes mean?
P and S generally describe open-market or private purchases and sales. A, D, F, M, X, G, J, and V describe awards, issuer dispositions, tax withholding, exercises, gifts, other transactions, and voluntary early reports; review each filing and its footnotes for context.