Ranked by reported Q1 2026 13F market value
Share of total reported institutional value in MIAX held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | SUSQUEHANNA INTERNATIONAL GROUP, LLP | 3.6M | $140.7M | +5.9% | 3.945% | 0.02% |
| 2 | HORIZON KINETICS ASSET MANAGEMENT LLC | 3.5M | $134.3M | +89.7% | 3.766% | 1.46% |
| 3 | BlackRock, Inc. | 2.2M | $86.9M | +27.3% | 2.436% | 0.00% |
| 4 | CITADEL ADVISORS LLC | 1.7M | $65.9M | +145.0% | 1.848% | 0.03% |
| 5 | Invesco Ltd. | 1.6M | $61.7M | +23.9% | 1.729% | 0.01% |
| 6 | Alyeska Investment Group, L.P. | 1.4M | $56.3M | +12.6% | 1.579% | 0.16% |
| 7 | VANGUARD CAPITAL MANAGEMENT LLC | 1.4M | $55.1M | — | 1.544% | 0.00% |
| 8 | VANGUARD PORTFOLIO MANAGEMENT LLC | 1.4M | $53.5M | — | 1.500% | 0.00% |
| 9 | ADAGE CAPITAL PARTNERS GP, L.L.C. | 1.2M | $48.5M | +41.5% | 1.361% | 0.07% |
| 10 | AMERICAN CENTURY COMPANIES INC | 1.2M | $47.5M | -15.7% | 1.333% | 0.02% |
| 11 | MORGAN STANLEY | 1.1M | $44.6M | +419.3% | 1.251% | 0.00% |
| 12 | Allspring Global Investments Holdings, LLC | 1.1M | $43.8M | +19.3% | 1.214% | 0.07% |
| 13 | North Reef Capital Management LP | 1.0M | $39.5M | -19.8% | 1.107% | 1.36% |
| 14 | Ghisallo Capital Management LLC | 1.0M | $38.9M | +79.4% | 1.091% | 1.07% |
| 15 | BANK OF AMERICA CORP /DE/ | 901K | $35.1M | +196.5% | 0.983% | 0.00% |
| 16 | TWO SIGMA INVESTMENTS, LP | 894K | $34.8M | +536.9% | 0.975% | 0.03% |
| 17 | GEODE CAPITAL MANAGEMENT, LLC | 780K | $30.4M | +52.1% | 0.851% | 0.00% |
| 18 | STATE STREET CORP | 712K | $27.7M | +23.6% | 0.777% | 0.00% |
| 19 | BLAIR WILLIAM & CO/IL | 666K | $25.9M | +1.7% | 0.726% | 0.07% |
| 20 | Caldwell Investment Management Ltd. | 664K | $24.9M | -10.2% | 0.724% | 9.77% |
| 21 | BNP PARIBAS ARBITRAGE, SA | 572K | $22.3M | +199.7% | 0.625% | 0.01% |
| 22 | FRANKLIN RESOURCES INC | 568K | $22.1M | +33.0% | 0.620% | 0.01% |
| 23 | SEVEN GRAND MANAGERS, LLC | 550K | $21.4M | +37.5% | 0.600% | 1.43% |
| 24 | SEI INVESTMENTS CO | 526K | $20.5M | +54.7% | 0.574% | 0.02% |
| 25 | MILLENNIUM MANAGEMENT LLC | 519K | $20.2M | +82.2% | 0.566% | 0.01% |
denotes a marquee investor (Buffett, Burry, ARK, Tiger Global, Pershing Square, Baupost and other widely-followed managers). “% of Fund” shows how much of that investor’s total 13F portfolio is invested in MIAX — a direct measure of their conviction.
Filings activity in MIAX during Q1 2026, grouped by how each filer changed its position.
3 quarters of 13F filings · Δ columns show change vs prior quarter
| Quarter | Inst. Holders | Δ Holders | Ownership % | Δ Ownership | Total 13F Value | Δ Value |
|---|---|---|---|---|---|---|
| Q1 2026 | 199 | +23% | 43.18% | +5.51 pp | $1.71B | +15% |
| Q4 2025 | 162 | +41% | 37.67% | +14.89 pp | $1.49B | +65% |
| Q3 2025 | 115 | — | 22.78% | — | $904M | — |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Δ columns compare to the immediately prior filed quarter.
Quick answers to the most common questions about buying MIAX stock.
Based on Q1 2026 13F filings, institutional ownership of Miami International Holdings, Inc. stands at 43.2%, held across 199 reporting institutions.
SUSQUEHANNA INTERNATIONAL GROUP, LLP is the largest reported institutional holder of MIAX, with approximately 3,615,646 shares worth $0.14B as of Q1 2026.
Yes — 4 widely-followed marquee investors appear among the top 25 institutional holders of MIAX, including SUSQUEHANNA INTERNATIONAL GROUP, LLP, CITADEL ADVISORS LLC, TWO SIGMA INVESTMENTS, LP, MILLENNIUM MANAGEMENT LLC.
Our composite Smart Money Score for MIAX is 80 out of 100 (Strong Smart Money). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
78 institutions opened new positions in MIAX during Q1 2026, while 41 fully exited. 62 added to existing positions and 57 trimmed.
MIAX institutional ownership rose by 5.51 percentage points quarter-over-quarter, with a net change of +37 holders.
The top 10 institutions account for 43.8% of all reported 13F value in MIAX, and the top 25 account for 70.2%.
All data is sourced from SEC Form 13F filings, which institutional investment managers with at least $100M in assets are required to file each quarter. We process every 13F filing from EDGAR and recompute the aggregates after each cycle. Insider transactions are sourced from Form 4 filings.
Miami International Holdings, Inc. (MIAX) Institutional Ownership