MIAMI INTL HLDGS INC MIAX
COM · Common Stock · CUSIP 59356Q108
Holdings company for MIAX exchanges and other entities
- SectorFinancials
- IndustrySecurity Brokers, Dealers & Flotation Companies
- HeadquartersPrinceton, NJ
- Websitemiaxoptions.com
- FilingsSEC EDGAR
* Summed across managers. Shares that two managers' reports both contain – a subsidiary's holdings that its parent's report includes too, or a sub-adviser's in its client's – are counted once ($981.2k this quarter). Holder counts are more reliable. Shares outstanding: 81.4m as of 2025-10-31, from the company's own SEC filing; the percentage can still exceed 100%: lent-out shares are counted by the lender and the buyer, and some reports overlap without saying so. Implied quarter-end price ≈ $44.21. Options: 4 managers hold calls ($6.4m notional), 4 hold puts ($3.5m).
Trends to Q4 2025
Institutional holders
Managers reporting a position, each quarter
Numbers
| Quarter | Holders |
|---|---|
| Q3 2025 | 116 |
| Q4 2025 | 162 |
Calls vs puts
Options held, notional value, last 4 quarters. P/C = puts ÷ calls
Numbers
| Quarter | Calls | Puts | P/C |
|---|---|---|---|
| Q1 2025 | $0 | $0 | — |
| Q2 2025 | $0 | $0 | — |
| Q3 2025 | $11.5m | $7.3m | 0.63 |
| Q4 2025 | $6.4m | $3.5m | 0.55 |
Biggest buyers
| AMERICAN CENTURY COMPANIES INC | Added | +1.2m |
| T. Rowe Price Investment Management, Inc. | Added | +1.1m |
| BlackRock, Inc. | Added | +1.0m |
| Invesco Ltd. | Added | +820.2k |
| VANGUARD GROUP INC | Added | +545.8k |
| North Reef Capital Management LP | Added | +539.2k |
| STATE STREET CORP | Added | +519.9k |
| Allspring Global Investments Holdings, LLC | Added | +478.4k |
| HORIZON KINETICS ASSET MANAGEMENT LLC | Added | +437.4k |
| GOLDMAN SACHS GROUP INC | Added | +387.5k |
Biggest sellers
| JPMORGAN CHASE & CO | Reduced | -809.1k |
| CITADEL ADVISORS LLC | Reduced | -355.5k |
| MORGAN STANLEY | Reduced | -300.1k |
| PRICE T ROWE ASSOCIATES INC /MD/ | Reduced | -268.3k |
| Gillson Capital LP | Sold out | -206.9k |
| ROYAL BANK OF CANADA | Reduced | -198.4k |
| Jain Global LLC | Sold out | -153.8k |
| Freestone Grove Partners LP | Sold out | -125.0k |
| MALTESE CAPITAL MANAGEMENT LLC | Reduced | -121.3k |
| Schonfeld Strategic Advisors LLC | Reduced | -117.7k |
Biggest calls
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Reduced | $4.2m95.4k shares |
| CITADEL ADVISORS LLC | Reduced | $1.7m38.9k shares |
| IMC-Chicago, LLC | New | $466.0k10.5k shares |
| SIMPLEX TRADING, LLC | Reduced | $17.8k400 shares |
Biggest puts
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Reduced | $1.5m33.7k shares |
| CITADEL ADVISORS LLC | Reduced | $1.4m32.6k shares |
| JANE STREET GROUP, LLC | Reduced | $359.5k8.1k shares |
| SIMPLEX TRADING, LLC | Reduced | $221.9k5.0k shares |
Options at notional value: the value of the shares the contracts control, as filers report them, not what the options cost. Not included in the holders, shares or buying above.
Major shareholders (over 5%)
Anyone who owns more than 5% of a class of the company's shares has to say so: on Schedule 13D if they may try to influence or control the company, on 13G if they're a passive investor, and update it as the stake changes. Each holder's latest filing, from 19 Dec 2024 on; percentages are of the share class, as the holder worked them out.
| Holder | Stake |
|---|---|
HORIZON KINETICS ASSET MANAGEMENT LLC
13D · may seek influence
-4.4 pts · filed 2026-05-21
Stated purposeHKAM acquired the securities reported herein on behalf of the Managed Accounts for investment purposes. In the ordinary course of its business, HKAM intends to regularly review its equity interest in the Issuer and may, from time to time, acquire additional shares or other securities of the Issuer. While HKAM has no present intention to dispose of all or any portion of the shares beneficially owned by Managed Accounts, it may sell shares from time to time for a number of reasons, not limited to client requests, regulatory or investment limitations or other reasons. Any such sales of securities of the Issuer may be in the open market, privately negotiated transactions or otherwise. On May 19, 2026, HKAM distributed 4,084,261 shares in-kind on a pro rata basis without consideration to the b… Full filing |
7.8% |
| BlackRock, Inc. 13G · institution +1.1 pts · filed 2026-10-27 | 6.2% |
| T. Rowe Price Investment Management, Inc. 13G · institution new · filed 2026-08-14 | 5.3% |
Insider purchases and sales in Q4 2025
Shares bought or sold by the company's own officers, directors and 10% owners, in the open market or privately, as they reported to the SEC on Form 4 (due within two business days of the trade). Grants, option exercises, shares withheld for tax and gifts aren't included.
Officers and directors buying vs selling
Number of people, by quarter (10% owners not included)
Numbers
| Quarter | Buying | Bought | Selling | Sold | Sold under a plan |
|---|---|---|---|---|---|
| Q1 2024 | 0 | — | 0 | — | — |
| Q2 2024 | 0 | — | 0 | — | — |
| Q3 2024 | 0 | — | 0 | — | — |
| Q4 2024 | 0 | — | 0 | — | — |
| Q1 2025 | 0 | — | 0 | — | — |
| Q2 2025 | 0 | — | 0 | — | — |
| Q3 2025 | 11 | $2.0m | 0 | — | — |
| Q4 2025 | 1 | $100.1k | 0 | — | — |
| Date | Insider | Trade | Value |
|---|---|---|---|
| 2025-12-12 | STAHL MURRAY +1 Director · Horizon Kinetics Asset Management LLC | Bought | $100.0k2.4k shares |
| 2025-10-03 | STAHL MURRAY +1 Director · Horizon Kinetics Asset Management LLC | Bought | $842 shares |
Their holding: how much the trade added to or took from the insider's holding (direct, or the trust or fund named). The same trade is sometimes reported by more than one insider, such as a fund and the director who represents it; totals count it once. A value is left blank where the reported price is far from the market price (usually a typo).
Holders, Q4 2025
| Manager | Shares | Change |
|---|---|---|
| T. Rowe Price Investment Management, Inc. 0.06% of their portfolio | 3.5m $156.9m | Added +1.1m |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP 0.20% of their portfolio | 3.3m $145.8m | Added +100 |
| VANGUARD GROUP INC 0.00% of their portfolio | 1.9m $85.6m | Added +545.8k |
| HORIZON KINETICS ASSET MANAGEMENT LLC 1.09% of their portfolio | 1.8m $80.8m | Added +437.4k |
| BlackRock, Inc. 0.00% of their portfolio | 1.8m $77.8m | Added +1.0m |
| AMERICAN CENTURY COMPANIES INC 0.03% of their portfolio | 1.4m $64.3m | Added +1.2m |
| Alyeska Investment Group, L.P. 0.16% of their portfolio | 1.3m $57.1m | Added +20.4k |
| Invesco Ltd. 0.01% of their portfolio | 1.3m $56.8m | Added +820.2k |
| North Reef Capital Management LP 2.26% of their portfolio | 1.3m $56.1m | Added +539.2k |
| Allspring Global Investments Holdings, LLC 0.07% of their portfolio | 932.1k $40.7m | Added +478.4k |
| ADAGE CAPITAL PARTNERS GP, L.L.C. 0.06% of their portfolio | 881.3k $39.1m | Added +249.7k |
| JPMORGAN CHASE & CO 0.00% of their portfolio | 814.3k $36.1m | Reduced -809.1k |
| Caldwell Investment Management Ltd. 20.74% of their portfolio | 738.8k $33.7m | Added +75.0k |
| LORD, ABBETT & CO. LLC 0.09% of their portfolio | 659.7k $29.3m | Added +360.5k |
| BLAIR WILLIAM & CO/IL 0.08% of their portfolio | 654.8k $29.1m | Added +291.1k |
| JANE STREET GROUP, LLC 0.03% of their portfolio | 638.0k $28.3m | Added +148.5k |
| CITADEL ADVISORS LLC 0.02% of their portfolio | 619.6k $27.5m | Reduced -355.5k |
| WELLINGTON MANAGEMENT GROUP LLP 0.00% of their portfolio | 616.1k $27.3m | Added +33.0k |
| GOLDMAN SACHS GROUP INC 0.00% of their portfolio | 580.7k $25.8m | Added +387.5k |
| STATE STREET CORP 0.00% of their portfolio | 576.4k $25.6m | Added +519.9k |
| Ghisallo Capital Management LLC 1.10% of their portfolio | 557.5k $24.7m | Added +282.5k |
| Driehaus Capital Management LLC 0.16% of their portfolio | 532.4k $23.6m | Added +340.8k |
| GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio | 512.8k $22.8m | Added +353.4k |
| AMERIPRISE FINANCIAL INC 0.00% of their portfolio | 447.5k $19.9m | Added +241.3k |
| FRANKLIN RESOURCES INC 0.00% of their portfolio | 427.2k $19.0m | Reduced -5.1k |
| SEVEN GRAND MANAGERS, LLC 1.35% of their portfolio | 400.0k $17.8m | Added +100.0k |
| VICTORY CAPITAL MANAGEMENT INC 0.01% of their portfolio | 392.1k $17.4m | Added +89.9k |
| SEI INVESTMENTS CO 0.01% of their portfolio | 340.3k $15.1m | Added +239.1k |
| INTRINSIC EDGE CAPITAL MANAGEMENT LLC 2.78% of their portfolio | 322.5k $14.3m | Reduced -25.9k |
| BANK OF AMERICA CORP /DE/ 0.00% of their portfolio | 303.9k $13.5m | Added +111.2k |
| Burkehill Global Management, LP 0.85% of their portfolio | 290.0k $12.9m | Added +140.0k |
| Jump Financial, LLC 0.16% of their portfolio | 285.3k $12.7m | Added +266.3k |
| MILLENNIUM MANAGEMENT LLC 0.01% of their portfolio | 284.7k $12.6m | Added +126.2k |
| Delta Global Management LP 0.90% of their portfolio | 279.0k $12.4m | Added +228.5k |
| NORGES BANK 0.00% of their portfolio | 277.2k $12.3m | Not comparable |
| MASSACHUSETTS FINANCIAL SERVICES CO /MA/ 0.00% of their portfolio | 273.9k $12.2m | Reduced -23.8k |
| Woodline Partners LP 0.04% of their portfolio | 261.1k $11.6m | Unchanged |
| Penn Capital Management Company, LLC 0.89% of their portfolio | 252.1k $11.2m | New |
| AXIOM INVESTORS LLC /DE 0.09% of their portfolio | 243.2k $10.8m | New |
| HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND 0.02% of their portfolio | 234.2k $10.4m | Added +34.2k |
| MORGAN STANLEY 0.00% of their portfolio | 220.9k $9.8m | Reduced -300.1k |
| TOCQUEVILLE ASSET MANAGEMENT L.P. 0.14% of their portfolio | 220.8k $9.8m | Reduced -9.9k |
| FEDERATED HERMES, INC. 0.01% of their portfolio | 200.0k $8.9m | Reduced -50.0k |
| RENAISSANCE TECHNOLOGIES LLC 0.01% of their portfolio | 195.1k $8.7m | New |
| BNP PARIBAS FINANCIAL MARKETS 0.01% of their portfolio | 191.0k $8.5m | New |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.00% of their portfolio | 187.1k $8.3m | Added +98.6k |
| ROYCE & ASSOCIATES LP 0.08% of their portfolio | 181.5k $8.1m | New |
| Monashee Investment Management LLC 4.38% of their portfolio | 175.0k $7.8m | Added +25.0k |
| Lykos Global Management, LP 5.49% of their portfolio | 175.0k $7.8m | First filing |
| NORTHERN TRUST CORP 0.00% of their portfolio | 169.6k $7.5m | Added +139.5k |
| UBS Group AG 0.00% of their portfolio | 162.9k $7.2m | Added +154.9k |
| NEW YORK STATE COMMON RETIREMENT FUND 0.01% of their portfolio | 162.2k $7.2m | New |
| SOROS FUND MANAGEMENT LLC 0.09% of their portfolio | 154.6k $6.9m | Added +50.3k |
| Optiver Holding B.V. 0.00% of their portfolio | 152.3k $6.8k | New |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE 0.01% of their portfolio | 146.9k $6.5m | Added +104.0k |
| TWO SIGMA INVESTMENTS, LP 0.01% of their portfolio | 140.3k $6.2m | Added +90.3k |
| Unisphere Establishment 0.04% of their portfolio | 135.0k $6.0m | Added +35.0k |
| PRICE T ROWE ASSOCIATES INC /MD/ 0.00% of their portfolio | 130.5k $5.8m | Reduced -268.3k |
| Polar Capital Holdings Plc 0.03% of their portfolio | 124.0k $5.5m | New |
| LMR Partners LLP 0.05% of their portfolio | 109.8k $4.9m | Unchanged |
| KING LUTHER CAPITAL MANAGEMENT CORP 0.02% of their portfolio | 103.8k $4.6m | New |
| RAYMOND JAMES FINANCIAL INC 0.00% of their portfolio | 102.4k $4.5m | Added +89.5k |
| Hudson Bay Capital Management LP 0.03% of their portfolio | 101.6k $4.5m | Added +60.4k |
| Schonfeld Strategic Advisors LLC 0.02% of their portfolio | 100.0k $4.4m | Reduced -117.7k |
| Quinn Opportunity Partners LLC 0.17% of their portfolio | 88.5k $3.9m | Reduced -74.1k |
| TD Asset Management Inc 0.00% of their portfolio | 80.5k $3.6m | Added +17.0k |
| Coastal Bridge Advisors, LLC 0.26% of their portfolio | 77.4k $3.4m | Added +850 |
| Russell Investments Group, Ltd. 0.00% of their portfolio | 76.4k $3.4m | New |
| MAD RIVER INVESTORS 1.52% of their portfolio | 75.0k $3.3m | Added +450 |
| Blackstone Inc. 0.01% of their portfolio | 75.0k $3.3m | Added +25.0k |
| Maven Securities LTD 0.39% of their portfolio | 69.9k $3.1m | New |
| Capelight Capital Asset Management LP 2.77% of their portfolio | 63.0k $2.8m | First filing |
| Bank of New York Mellon Corp 0.00% of their portfolio | 60.4k $2.7m | Added +53.8k |
| one8zero8, LLC 0.57% of their portfolio | 58.4k $2.6m | New |
| BARCLAYS PLC 0.00% of their portfolio | 57.1k $2.5m | Added +41.2k |
| TUDOR INVESTMENT CORP ET AL 0.01% of their portfolio | 56.0k $2.5m | Added +10.5k |
| CREDIT AGRICOLE S A 0.01% of their portfolio | 51.0k $2.3m | New |
| Harvey Partners, LLC 0.20% of their portfolio | 50.0k $2.2m | Unchanged |
| Panoramic Capital, LLC 1.17% of their portfolio | 46.1k $2.0m | New |
| STATE OF WISCONSIN INVESTMENT BOARD 0.00% of their portfolio | 42.6k $1.9m | New |
| Calamos Advisors LLC 0.01% of their portfolio | 41.4k $1.8m | New |
| OSAIC HOLDINGS, INC. 0.00% of their portfolio | 40.2k $1.8m | Added +7.5k |
| Covalis Capital LLP 0.14% of their portfolio | 40.0k $1.8m | New |
| Nuveen, LLC 0.00% of their portfolio | 39.1k $1.7m | New |
| MALTESE CAPITAL MANAGEMENT LLC 0.30% of their portfolio | 38.7k $1.7m | Reduced -121.3k |
| XTX Topco Ltd 0.04% of their portfolio | 38.4k $1.7m | New |
| Pekin Hardy Strauss, Inc. 0.15% of their portfolio | 36.3k $1.6m | Added +10.6k |
| WELLS FARGO & COMPANY/MN 0.00% of their portfolio | 35.6k $1.6m | Added +32.1k |
| Grandeur Peak Global Advisors, LLC 0.19% of their portfolio | 32.0k $1.4m | Added +439 |
| Quadrature Capital Ltd 0.01% of their portfolio | 31.9k $1.4m | New |
| Swiss National Bank 0.00% of their portfolio | 31.8k $1.4m | New |
| ELEMENT CAPITAL MANAGEMENT LLC 0.64% of their portfolio | 27.9k $1.2m | New |
| RHUMBLINE ADVISERS 0.00% of their portfolio | 27.4k $1.2m | New |
| Bullseye Asset Management LLC 0.64% of their portfolio | 26.7k $1.2m | New |
| Hound Partners, LLC 0.15% of their portfolio | 25.0k $1.1m | Unchanged |
| Atlas Wealth Partners, LLC 1.19% of their portfolio | 24.5k $1.1m | Added +2.6k |
| ALLIANCEBERNSTEIN L.P. 0.00% of their portfolio | 23.1k $1.0m | New |
| VARCOV Co. 0.39% of their portfolio | 22.4k $993.6k | First filing |
| Symmetry Investments LP 0.18% of their portfolio | 22.0k $976.4k | New |
| FIRST TRUST ADVISORS LP 0.00% of their portfolio | 21.7k $961.8k | Added +733 |