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 ($476.0k this quarter). Holder counts are more reliable. Shares outstanding: 99.2m as of 2026-07-31, 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 ≈ $37.18. Options: 9 managers hold calls ($27.6m notional), 9 hold puts ($24.0m).
Trends to Q2 2026
Institutional holders
Managers reporting a position, each quarter
Numbers
| Quarter | Holders |
|---|---|
| Q3 2025 | 116 |
| Q4 2025 | 162 |
| Q1 2026 | 203 |
| Q2 2026 | 206 |
Buyers vs sellers
Managers adding to or starting a position, vs cutting or selling out
Numbers
| Quarter | Bought or added | Cut or sold out |
|---|---|---|
| Q4 2025 | 125 | 42 |
| Q1 2026 | 158 | 60 |
| Q2 2026 | 137 | 86 |
Calls vs puts
Options held, notional value, last 4 quarters. P/C = puts ÷ calls
Numbers
| Quarter | Calls | Puts | P/C |
|---|---|---|---|
| Q3 2025 | $11.5m | $7.3m | 0.63 |
| Q4 2025 | $6.4m | $3.5m | 0.55 |
| Q1 2026 | $13.4m | $11.0m | 0.82 |
| Q2 2026 | $27.6m | $24.0m | 0.87 |
Biggest buyers
| HORIZON KINETICS ASSET MANAGEMENT LLC | Added | +4.4m |
| BlackRock, Inc. | Added | +2.8m |
| VANGUARD PORTFOLIO MANAGEMENT LLC | Added | +2.4m |
| J Digital 6 LLC | New | +1.8m |
| VANGUARD CAPITAL MANAGEMENT LLC | Added | +1.8m |
| Balyasny Asset Management L.P. | New | +1.7m |
| BLAIR WILLIAM & CO/IL | Added | +1.1m |
| T. Rowe Price Investment Management, Inc. | Added | +887.4k |
| HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND | Added | +799.4k |
| STATE STREET CORP | Added | +720.6k |
Biggest sellers
| CITADEL ADVISORS LLC | Sold out | -1.6m |
| North Reef Capital Management LP | Reduced | -762.9k |
| Alyeska Investment Group, L.P. | Reduced | -598.7k |
| Ghisallo Capital Management LLC | Reduced | -500.0k |
| MILLENNIUM MANAGEMENT LLC | Reduced | -329.6k |
| Penn Capital Management Company, LLC | Sold out | -273.8k |
| RENAISSANCE TECHNOLOGIES LLC | Sold out | -271.5k |
| Woodline Partners LP | Sold out | -261.1k |
| TUDOR INVESTMENT CORP ET AL | Sold out | -259.8k |
| Allspring Global Investments Holdings, LLC | Reduced | -254.6k |
Biggest calls
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Added | $11.2m302.4k shares |
| CITADEL ADVISORS LLC | Added | $4.7m125.2k shares |
| IMC-Chicago, LLC | Added | $4.6m123.9k shares |
| JANE STREET GROUP, LLC | Added | $2.6m70.3k shares |
| Caption Management, LLC | New | $1.9m51.0k shares |
| Parallax Volatility Advisers, L.P. | New | $1.1m30.0k shares |
| D. E. Shaw & Co., Inc. | New | $1.1m29.9k shares |
| TORNO CAPITAL, LLC | Not comparable | $185.8k5.0k shares |
| SIMPLEX TRADING, LLC | Added | $174.7k4.7k shares |
Biggest puts
| Swan Global Investments, LLC | New | $11.3m322.2k shares |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Added | $5.1m138.1k shares |
| CITADEL ADVISORS LLC | Added | $2.0m54.1k shares |
| JANE STREET GROUP, LLC | Added | $1.6m43.9k shares |
| IMC-Chicago, LLC | Added | $1.5m41.7k shares |
| SIMPLEX TRADING, LLC | Reduced | $1.4m37.6k shares |
| SIG BROKERAGE, LP | Reduced | $743.2k20.0k shares |
| TUDOR INVESTMENT CORP ET AL | New | $204.4k5.5k shares |
| TORNO CAPITAL, LLC | Not comparable | $100.3k2.7k 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 since 1 Apr 2026
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 |
|---|---|---|---|---|---|
| Q4 2024 | 0 | — | 0 | — | — |
| Q1 2025 | 0 | — | 0 | — | — |
| Q2 2025 | 0 | — | 0 | — | — |
| Q3 2025 | 11 | $2.0m | 0 | — | — |
| Q4 2025 | 1 | $100.1k | 0 | — | — |
| Q1 2026 | 1 | $622.5k | 5 | $6.6m | $4.4m |
| Q2 2026 | 0 | — | 10 | $32.6m | $32.6m |
| Q3 2026 | 0 | — | 10 | $36.0m | $36.0m |
| Date | Insider | Trade | Value |
|---|---|---|---|
| 2026-09-16 | Brown Shelly EVP, Chief Strategy Officer | Sold plan | $819.2k21.2k shares |
| 2026-09-03 | Gallagher Thomas P. Chairman & CEO, director · By Gallagher Investments, LLC | Sold plan | $2.0m47.0k shares |
| 2026-09-03 | Deitzel Edward EVP, CRO, CCO MIAX Exchanges | Sold plan | $464.3k11.0k shares |
| 2026-09-02 | Schafer Douglas M. JR EVP and CIO | Sold plan | $1.9m48.0k shares |
| 2026-09-02 | Comly Barbara J. EVP, GC & Corporate Secretary | Sold plan | $1.8m44.4k shares |
| 2026-09-02 | Teekell Judson Gray Director · By estate of Byrum W. Teekell | Sold plan | $230.6k5.5k shares |
| 2026-09-02 | Teekell Judson Gray Director | Sold plan | $122.7k3.0k shares |
| 2026-08-19 | Gallagher Thomas P. Chairman & CEO, director · By Gallagher Investments, LLC | Sold plan | $6.2m149.7k shares |
| 2026-08-17 | Emmons Lance EVP and CFO | Sold plan | $1.5m35.0k shares |
| 2026-08-17 | Schwarzkopf Cynthia Director | Sold plan | $214.2k5.0k shares |
| 2026-08-04 | Gallagher Thomas P. Chairman & CEO, director · By Gallagher Investments, LLC | Sold plan | $2.2m48.3k shares |
| 2026-08-04 | Schafer Douglas M. JR EVP and CIO | Sold plan | $2.2m48.0k shares |
| 2026-08-04 | Comly Barbara J. EVP, GC & Corporate Secretary | Sold plan | $2.0m44.4k shares |
| 2026-08-04 | Jayabalan Harish EVP, CISO and CRO | Sold plan | $918.0k20.0k shares |
| 2026-08-04 | Deitzel Edward EVP, CRO, CCO MIAX Exchanges | Sold plan | $503.6k11.0k shares |
| 2026-08-04 | Teekell Judson Gray Director | Sold plan | $137.4k3.0k shares |
| 2026-08-04 | Eckert Kurt M. Director | Sold plan | $48.7k1.1k shares |
| 2026-07-15 | Schwarzkopf Cynthia Director | Sold plan | $210.0k5.0k shares |
| 2026-07-13 | Gallagher Thomas P. Chairman & CEO, director · By Gallagher Investments, LLC | Sold plan | $3.0m70.0k shares |
| 2026-07-13 | Comly Barbara J. EVP, GC & Corporate Secretary | Sold plan | $1.2m28.0k shares |
| 2026-07-07 | Gallagher Thomas P. Chairman & CEO, director · By Gallagher Investments, LLC | Sold plan | $1.2m28.2k shares |
| 2026-07-06 | Gallagher Thomas P. Chairman & CEO, director · By Gallagher Investments, LLC | Sold plan | $1.8m41.8k shares |
| 2026-07-06 | Jayabalan Harish EVP, CISO and CRO | Sold plan | $842.4k20.0k shares |
| 2026-07-06 | Brown Shelly EVP, Chief Strategy Officer | Sold plan | $674.1k16.0k shares |
| 2026-07-06 | Deitzel Edward EVP, CRO, CCO MIAX Exchanges | Sold plan | $462.4k11.0k shares |
| 2026-07-02 | Schafer Douglas M. JR EVP and CIO | Sold plan | $2.0m48.0k shares |
| 2026-07-02 | Comly Barbara J. EVP, GC & Corporate Secretary | Sold plan | $1.2m28.0k shares |
| 2026-07-02 | Eckert Kurt M. Director | Sold plan | $206.6k5.2k shares |
| 2026-07-02 | Teekell Judson Gray Director | Sold plan | $120.0k3.0k shares |
| 2026-06-15 | Brown Shelly EVP, Chief Strategy Officer | Sold plan | $208.5k4.7k shares |
The latest 30 of 58 trades.
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, Q2 2026
| Manager | Shares | Change |
|---|---|---|
| HORIZON KINETICS ASSET MANAGEMENT LLC 3.30% of their portfolio | 7.8m $291.4m | Added +4.4m |
| BlackRock, Inc. 0.00% of their portfolio | 5.1m $188.5m | Added +2.8m |
| T. Rowe Price Investment Management, Inc. 0.12% of their portfolio | 5.0m $187.0m | Added +887.4k |
| VANGUARD PORTFOLIO MANAGEMENT LLC 0.01% of their portfolio | 3.8m $140.7m | Added +2.4m |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP 0.11% of their portfolio | 3.4m $124.7m | Added +58.7k |
| VANGUARD CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 3.2m $117.6m | Added +1.8m |
| Invesco Ltd. 0.01% of their portfolio | 2.0m $75.1m | Added +435.6k |
| J Digital 6 LLC 39.72% of their portfolio | 1.8m $67.2m | New |
| BLAIR WILLIAM & CO/IL 0.17% of their portfolio | 1.8m $65.8m | Added +1.1m |
| Balyasny Asset Management L.P. 0.11% of their portfolio | 1.7m $62.5m | New |
| AMERICAN CENTURY COMPANIES INC 0.03% of their portfolio | 1.6m $59.0m | Added +365.7k |
| STATE STREET CORP 0.00% of their portfolio | 1.4m $53.2m | Added +720.6k |
| JPMORGAN CHASE & CO 0.00% of their portfolio | 1.4m $52.7m | Added +189.9k |
| GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio | 1.4m $51.9m | Added +615.9k |
| ADAGE CAPITAL PARTNERS GP, L.L.C. 0.06% of their portfolio | 1.1m $42.5m | Reduced -103.1k |
| HEALTHCARE OF ONTARIO PENSION PLAN TRUST FUND 0.06% of their portfolio | 1.0m $38.6m | Added +799.4k |
| LORD, ABBETT & CO. LLC 0.11% of their portfolio | 1.0m $37.2m | Added +140.2k |
| MORGAN STANLEY 0.00% of their portfolio | 950.6k $35.3m | Reduced -196.4k |
| TWO SIGMA INVESTMENTS, LP 0.02% of their portfolio | 888.1k $33.0m | Reduced -5.6k |
| Allspring Global Investments Holdings, LLC 0.05% of their portfolio | 857.7k $33.5m | Reduced -254.6k |
| BANK OF AMERICA CORP /DE/ 0.00% of their portfolio | 857.0k $31.8m | Reduced -43.9k |
| Alyeska Investment Group, L.P. 0.08% of their portfolio | 848.8k $31.5m | Reduced -598.7k |
| PRICE T ROWE ASSOCIATES INC /MD/ 0.00% of their portfolio | 844.5k $31.4m | Added +685.3k |
| FRANKLIN RESOURCES INC 0.01% of their portfolio | 784.8k $29.2m | Added +216.6k |
| Walleye Capital LLC 0.13% of their portfolio | 728.0k $27.1m | Added +689.5k |
| WESTFIELD CAPITAL MANAGEMENT CO LP 0.09% of their portfolio | 700.7k $26.0m | New |
| NewEdge Advisors, LLC 0.08% of their portfolio | 681.6k $25.3m | Added +642.6k |
| Nuveen, LLC 0.01% of their portfolio | 668.1k $24.8m | Added +436.2k |
| Caldwell Investment Management Ltd. 14.63% of their portfolio | 600.0k $22.3m | Reduced -63.8k |
| Assenagon Asset Management S.A. 0.01% of their portfolio | 595.7k $22.1m | New |
| UBS Group AG 0.00% of their portfolio | 567.8k $21.1m | Added +144.4k |
| Driehaus Capital Management LLC 0.12% of their portfolio | 566.1k $21.0m | Added +169.4k |
| NORTHERN TRUST CORP 0.00% of their portfolio | 562.3k $20.9m | Added +328.4k |
| AMERIPRISE FINANCIAL INC 0.00% of their portfolio | 559.5k $20.8m | Added +50.0k |
| SEVEN GRAND MANAGERS, LLC 0.82% of their portfolio | 550.0k $20.4m | Unchanged |
| Ghisallo Capital Management LLC 0.36% of their portfolio | 500.0k $18.6m | Reduced -500.0k |
| Clearstead Advisors, LLC 0.17% of their portfolio | 473.9k $17.6m | Reduced -29.7k |
| ROYCE & ASSOCIATES LP 0.14% of their portfolio | 452.8k $16.8m | Added +143.5k |
| VICTORY CAPITAL MANAGEMENT INC 0.01% of their portfolio | 427.4k $15.9m | Added +37.9k |
| MASSACHUSETTS FINANCIAL SERVICES CO /MA/ 0.00% of their portfolio | 406.3k $15.1m | Added +65.0k |
| GOLDMAN SACHS GROUP INC 0.00% of their portfolio | 399.8k $14.9m | Reduced -26.5k |
| BNP PARIBAS FINANCIAL MARKETS 0.01% of their portfolio | 394.7k $14.7m | Reduced -177.8k |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.00% of their portfolio | 373.5k $13.9m | Added +136.2k |
| D. E. Shaw & Co., Inc. 0.01% of their portfolio | 355.5k $13.2m | Added +34.8k |
| TOCQUEVILLE ASSET MANAGEMENT L.P. 0.17% of their portfolio | 338.2k $12.6m | Added +26.1k |
| VANGUARD FIDUCIARY TRUST CO 0.00% of their portfolio | 315.3k $11.7m | Added +112.7k |
| SEI INVESTMENTS CO 0.01% of their portfolio | 307.1k $11.4m | Reduced -219.3k |
| BARCLAYS PLC 0.00% of their portfolio | 295.8k $11.0m | Added +21.5k |
| Burkehill Global Management, LP 0.39% of their portfolio | 290.0k $10.8m | Unchanged |
| MAD RIVER INVESTORS 4.02% of their portfolio | 289.0k $10.7m | Added +207.8k |
| MARSHALL WACE, LLP 0.01% of their portfolio | 287.5k $10.7m | Added +164.9k |
| Langdon Equity Partners 5.87% of their portfolio | 282.5k $10.5m | New |
| Nearwater Capital Markets, Ltd 0.18% of their portfolio | 279.0k $10.4m | New |
| JENNISON ASSOCIATES LLC 0.01% of their portfolio | 267.3k $9.9m | New |
| WELLINGTON MANAGEMENT GROUP LLP 0.00% of their portfolio | 262.2k $9.7m | Reduced -182.7k |
| Caprock Group, LLC 0.19% of their portfolio | 259.9k $9.7m | Added +159.3k |
| North Reef Capital Management LP 0.36% of their portfolio | 251.4k $9.3m | Reduced -762.9k |
| SG Americas Securities, LLC 0.01% of their portfolio | 242.5k $9.0m | Added +239.0k |
| NORGES BANK 0.00% of their portfolio | 237.9k $8.8m | Not comparable |
| York GP, Ltd. 6.79% of their portfolio | 230.7k $8.6m | New |
| FEDERATED HERMES, INC. 0.01% of their portfolio | 224.4k $8.3m | Added +23.3k |
| Philadelphia Financial Management of San Francisco, LLC 2.28% of their portfolio | 223.7k $8.3m | New |
| Bank of New York Mellon Corp 0.00% of their portfolio | 220.4k $8.2m | Added +142.4k |
| Schonfeld Strategic Advisors LLC 0.04% of their portfolio | 200.2k $7.4m | Added +42.5k |
| BlueCrest Capital Management Ltd 0.32% of their portfolio | 200.0k $7.4m | New |
| Hudson Bay Capital Management LP 0.03% of their portfolio | 190.2k $7.1m | Added +160.6k |
| MILLENNIUM MANAGEMENT LLC 0.00% of their portfolio | 189.1k $7.0m | Reduced -329.6k |
| Coastal Bridge Advisors, LLC 0.42% of their portfolio | 183.8k $6.8m | Added +105.7k |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE 0.01% of their portfolio | 177.3k $6.6m | Added +13.3k |
| XTX Topco Ltd 0.08% of their portfolio | 170.9k $6.3m | Added +141.7k |
| WELLS FARGO & COMPANY/MN 0.00% of their portfolio | 164.1k $6.1m | Added +102.9k |
| OSAIC HOLDINGS, INC. 0.01% of their portfolio | 157.9k $5.9m | Added +113.0k |
| Optiver Holding B.V. 0.08% of their portfolio | 152.3k $5.7m | Reduced -311 |
| NORTHWESTERN MUTUAL WEALTH MANAGEMENT CO 0.00% of their portfolio | 151.2k $5.6m | New |
| Sone Capital Management, LLC 0.39% of their portfolio | 138.9k $5.2m | New |
| HMV Wealth Advisors, LLC 2.00% of their portfolio | 138.0k $5.1m | Added +127.3k |
| Focus Partners Advisor Solutions, LLC 0.04% of their portfolio | 136.7k $5.1m | Added +126.4k |
| FJ Capital Management LLC 0.58% of their portfolio | 119.3k $4.4m | New |
| Moors & Cabot, Inc. 0.17% of their portfolio | 118.9k $4.4m | Added +80.4k |
| One Charles Private Wealth Services, LLC 1.01% of their portfolio | 118.4k $4.4m | New |
| RAYMOND JAMES FINANCIAL INC 0.00% of their portfolio | 116.4k $4.3m | Reduced -3.0k |
| HighTower Advisors, LLC 0.00% of their portfolio | 112.3k $4.2m | Added +83.5k |
| TD Asset Management Inc 0.00% of their portfolio | 109.7k $4.1m | Added +3.7k |
| Delta Global Management LP 0.44% of their portfolio | 109.7k $4.1m | Reduced -178.0k |
| INTRINSIC EDGE CAPITAL MANAGEMENT LLC 0.49% of their portfolio | 106.0k $3.9m | Reduced -170.0k |
| Qube Research & Technologies Ltd 0.00% of their portfolio | 101.1k $3.8m | Added +18.6k |
| Bullseye Asset Management LLC 1.85% of their portfolio | 98.2k $3.6m | Added +32.2k |
| RHUMBLINE ADVISERS 0.00% of their portfolio | 89.7k $3.3m | Added +60.5k |
| ALLIANCEBERNSTEIN L.P. 0.00% of their portfolio | 89.2k $3.5m | Added +62.9k |
| G2 Investment Partners Management LLC 0.58% of their portfolio | 85.0k $3.2m | Added +32.4k |
| Polar Capital Holdings Plc 0.01% of their portfolio | 82.6k $3.1m | Reduced -36.1k |
| MBL Wealth, LLC 0.20% of their portfolio | 78.9k $2.9m | Reduced -8.1k |
| CITIGROUP INC 0.00% of their portfolio | 77.3k $2.9m | Reduced -28.1k |
| DEUTSCHE BANK AG\ 0.00% of their portfolio | 75.1k $2.8m | Added +54.6k |
| SPIREPOINT PRIVATE CLIENT, LLC 0.21% of their portfolio | 68.9k $2.6m | Unchanged |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP 0.00% of their portfolio | 63.3k $2.4m | Reduced -86.6k |
| Voleon Capital Management LP 0.04% of their portfolio | 58.2k $2.2m | Added +34.2k |
| EagleClaw Capital Managment, LLC 0.29% of their portfolio | 57.8k $2.1m | New |
| ROYAL BANK OF CANADA 0.00% of their portfolio | 53.3k $2.0m | Added +43.0k |
| CREDIT AGRICOLE S A 0.00% of their portfolio | 51.0k $1.9m | Unchanged |