---
schema_version: "secwatch.filing_event.v1"
accession: "0001628280-25-040532"
form_type: "8-K"
ticker: "MIAX"
cik: "0001438472"
company_name: "MIAMI INTERNATIONAL HOLDINGS, INC."
filed_at: "2025-08-15T23:59:59+00:00"
generated_at: "2026-05-17T12:23:02.139615+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.9
calibrated_materiality_score: 0.9
confidence: "high"
source: SEC EDGAR
---

# Miami International Holdings completes IPO of 17.25M shares at $23, gross proceeds $396.8M

## Summary
- IPO closed August 15, 2025, with 17,250,000 shares sold at $23.00 per share, including full underwriter over-allotment of 2,250,000 shares.
- Gross proceeds to company of $396.8 million before underwriting discounts and expenses.
- All outstanding Series B preferred and nonvoting common converted into 4,525,000 common shares immediately prior to IPO closing.

## SEC filing metadata
- accession: 0001628280-25-040532
- form_type: 8-K
- ticker: MIAX
- cik: 0001438472
- company_name: MIAMI INTERNATIONAL HOLDINGS, INC.
- filed_at: 2025-08-15T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.9
- calibrated_materiality_score: 0.9
- confidence: high
- sec_items: 3.02, 8.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1438472/000162828025040532/0001628280-25-040532-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1438472/000162828025040532/miamiinternationalholdings.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001628280-25-040532
- JSON: https://secwatch.observer/filing/0001628280-25-040532.json
- Plain text: https://secwatch.observer/filing/0001628280-25-040532.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.