MIAX MIAMI INTERNATIONAL HOLDINGS, INC.
Executive Summary
Four mega-passive institutional investors (Vanguard, BlackRock, State Street, Fidelity) collectively added $102.6M in MIAX shares during Q4 2025, while Morgan Stanley trimmed $11.2M. The buying is dominated by index-fund rebalancing, not active manager conviction, and the 45-day disclosure lag means positions may have already been adjusted. The cluster signals passive accumulation but lacks the active-manager catalyst that typically drives outsized returns.
Key Financial Metrics
Institutional Positions
Net institutional flow: $102.6M
▲ Buyers (4)
| Institution | Action | Change | Position Value | Value Δ |
|---|---|---|---|---|
| Vanguard | ADD | +39.5% | $85.6M | $29.9M |
| BlackRock | DOUBLED | +147.8% | $77.8M | $49.3M |
| State Street | DOUBLED | +921.1% | $25.6M | $23.3M |
| Fidelity | DOUBLED | +1866.7% | $65.0K | $62.0K |
▼ Sellers (1)
| Institution | Action | Change | Prev Value | Value Δ |
|---|---|---|---|---|
| Morgan Stanley | TRIM | -57.6% | $21.0M | -$11.2M |
Actionable Insight
The cluster is dominated by passive rebalancing, not active conviction. Monitor for any subsequent 13F filings or activist 13D to confirm a catalyst. The 45-day lag means the buying may have already been reversed — check recent price action for signs of distribution.
Key Facts
- 4 mega-passive buyers added $102.6M net; 1 seller reduced by $11.2M
- BlackRock doubled its position (+147.8%) to $77.8M; State Street added 921.1% to $25.6M
- All buyers are passive/index-fund managers — no active hedge fund or activist involvement
- Morgan Stanley trimmed 57.6% of its position, selling $11.2M
- 13F data reflects Q4 2025 quarter-end positions, filed with ~45-day lag
Financial Impact
Net institutional accumulation of $102.6M across 4 buyers, offset by $11.2M in selling from Morgan Stanley
Risk Factors
- Passive buying may be index-driven and not reflect fundamental thesis
- 45-day disclosure lag: positions may have been unwound since quarter-end
- Morgan Stanley's trim could signal institutional rotation ahead of known headwinds
Market Snapshot
Documents Analyzed
This report is based on 1 institutional 13F filing from SEC EDGAR.
| Document | Accession Number |
|---|---|
| INST-CLUSTER Data (Synthetic) | inst-cluster-MIAX-2025-Q4 |
Filters
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Jun 17, 2026
3d ago
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8-K
| $37.85 awaiting T+1 | awaiting T+1 | — | — |
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Jun 17, 2026
3d ago
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Insider Cluster
| $37.85 awaiting T+1 | awaiting T+1 | — | — |
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Jun 17, 2026
3d ago
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Insider Cluster
| $37.85 awaiting T+1 | awaiting T+1 | — | — |
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Jun 17, 2026
3d ago
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Insider Cluster
| $37.85 awaiting T+1 | awaiting T+1 | — | — |
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Jun 17, 2026
3d ago
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Insider Cluster
| $37.85 awaiting T+1 | awaiting T+1 | — | — |
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Jun 17, 2026
3d ago
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Insider Cluster
| $37.85 awaiting T+1 | awaiting T+1 | — | — |
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Jun 17, 2026
3d ago
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Insider Cluster
| $37.85 awaiting T+1 | awaiting T+1 | — | — |
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Jun 17, 2026
3d ago
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Insider Cluster
| $37.85 awaiting T+1 | awaiting T+1 | — | — |
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Jun 12, 2026
8d ago
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Insider Cluster
| $44.11 $40.24 | ▼ −8.77% | ▼ −8.18% | — |
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Jun 12, 2026
8d ago
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Insider Cluster
| $44.11 $40.24 | ▼ −8.77% | ▼ −8.18% | — |
US Market Status
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