---
schema_version: "secwatch.filing_event.v1"
accession: "0001438472-25-000016"
form_type: "8-K"
ticker: "MIAX"
cik: "0001438472"
company_name: "MIAMI INTERNATIONAL HOLDINGS, INC."
filed_at: "2025-11-26T23:59:59+00:00"
generated_at: "2026-05-16T16:26:53.459202+00:00"
event_type: "m_and_a"
sentiment: "positive"
materiality_score: 0.7
calibrated_materiality_score: 0.7
confidence: "high"
source: SEC EDGAR
---

# MIAX sells 90% of MIAXdx to Robinhood & Susquehanna; retains 10% stake

## Summary
- MIAX to sell 90% of MIAXdx to Robinhood Markets (NASDAQ:HOOD) in partnership with Susquehanna International Group.
- MIAX will retain the remaining 10% equity interest in MIAXdx, a CFTC-regulated DCM and DCO.
- Transaction expected to close in Q1 2026, subject to customary closing conditions and CFTC filings.
- CEO Thomas Gallagher cites expedited access to prediction markets and strategic alignment with industry leaders.
- No purchase price disclosed; MIAX's retained stake provides continued exposure to prediction markets.

## SEC filing metadata
- accession: 0001438472-25-000016
- form_type: 8-K
- ticker: MIAX
- cik: 0001438472
- company_name: MIAMI INTERNATIONAL HOLDINGS, INC.
- filed_at: 2025-11-26T23:59:59+00:00
- event_type: m_and_a
- sentiment: positive
- materiality_score: 0.7
- calibrated_materiality_score: 0.7
- confidence: high
- sec_items: 8.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1438472/000143847225000016/0001438472-25-000016-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1438472/000143847225000016/miax-20251125.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001438472-25-000016
- JSON: https://secwatch.observer/filing/0001438472-25-000016.json
- Plain text: https://secwatch.observer/filing/0001438472-25-000016.txt

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