Form
SCHEDULE 13D/A
Active or control-oriented beneficial ownership filing.
Thomas P. Gallagher - 26 Aug 2025 SCHEDULE 13D/A Report for Miami International Holdings, Inc. (the "Issuer") Common Stock, $0.001 par value per share (the "Common Stock") (MIAX)
- Filing manager
- Thomas P. Gallagher
- Reporting owner
- Thomas P. Gallagher
- Beneficially owned shares
- 4,036,237 shares
- Large-stake signal
-
Ownership
4.9%Beneficial ownership of this reported class.
Shares
4,036,237 sharesShares beneficially owned as disclosed.
Event date
26 Aug 2025Date tied to the ownership event or amendment.
Accepted by SEC
28 Aug 2025EDGAR acceptance date.
How to read this large-stake filing
- Schedule 13D/G filings focus on beneficial ownership stakes, not a full portfolio.
- Compare this filing with the holder history and issuer page before treating the percentage as a current position.
- Use amendments to understand whether the disclosed stake increased, decreased, or changed reporting status.
- Class ownership
- 4.9%
- Symbol
- MIAX
- Shares outstanding
- 82,372,184 shares
- SEC form
- SCHEDULE 13D/A
- Accepted by SEC
- 28 Aug 2025, 16:30:05 UTC
- Event date
- 26 Aug 2025
- Prior SEC filing
- 21 Aug 2025
- Source filing
- View source filing
Ownership signal
CIK-linked ownership evidence from parsed SEC filings.
2 signals
Subject security
Names, identifiers, and filing context for this profile.
2 source fields
Source evidence
Original filing metadata and source links for verification.
5 source fields
Key filing fact
Thomas P. Gallagher disclosed 4.9% ownership in Miami International Holdings, Inc. (the "Issuer") Common Stock, $0.001 par value per share (the "Common Stock") (MIAX) on 26 Aug 2025.
Key facts
- Thomas P. Gallagher filed SCHEDULE 13D/A for Miami International Holdings, Inc. (the "Issuer") Common Stock, $0.001 par value per share (the "Common Stock") (MIAX).
- Disclosed ownership: 4.9%.
- Date of event: 26 Aug 2025.
Change
- Previous schedule filing date: 21 Aug 2025.
- Current filing was accepted on 28 Aug 2025, 16:30.
Research use
- This page turns one Schedule 13D/G filing into a quick large-stake read before the raw reporting-person rows.
- Use the linked SEC filing as the source of truth for ownership percentages, shares, and reporting-party details.
Evidence
Backed by Schedule 13D/13G
View source filing
Beneficial ownership values are sourced from the original SEC Schedule 13D/13G filing.
Reporting persons
Disclosed reporting parties (2)
Names, ownership percentages, voting power, signatures, titles, and CIKs as disclosed in this Schedule 13D/G filing.
| Name | Ownership | Shares owned | Sole voting power | Shared voting power | Signature | Title | CIK |
|---|---|---|---|---|---|---|---|
| Thomas P. Gallagher | 4.9% | 4,036,237 | 651,101 | 3,385,136 | Thomas P. Gallagher | /s/ Thomas P. Gallagher, Individually | 0002080477 |
| Gallagher Investments LLC | 4.1% | 3,385,136 | 0 | 3,385,136 | Gallagher Investments LLC | /s/ Thomas P. Gallagher, Manager |
CIK / CUSIP context first