MIAX
Miami International Holdings, Inc.
37.70$
-1.0%
vs. previous close
Closing price · As of: Sep 17, 2026
Ownership
Ownership Structure
Who owns Miami International Holdings, Inc. (MIAX)? This page shows the largest institutions and funds, the ownership structure and the latest insider transactions. 94.3% of the shares are freely tradable; institutional investors hold 57.4%.
Institutional ownership
?Share of the stock held by institutional investors (funds, banks, insurers) according to regulatory filings.
57.4%
Insiders
?Share of the stock held by the executives, founders and major shareholders of the company itself.
10.0%
Float
?Share of stock freely tradable on the market — not locked up in the hands of founders, insiders, or major shareholders.
94.3%
Short % of float
?Shares sold short as a percentage of the freely tradable float — high values signal many bets on falling prices.
8.6%
Shares Outstanding
?Total number of shares issued. Price times share count gives market cap.
99Mio.
Largest Shareholders
Institutions
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| T. Rowe Price Investment Management,Inc. | 4.18 | 4,145,618 | +17.2 | 03/31/2026 |
| Horizon Asset Management Inc/ny | 3.48 | 3,451,549 | +89.7 | 03/31/2026 |
| Susquehanna International Group, LLP | 3.32 | 3,296,346 | +0.3 | 03/31/2026 |
| BlackRock Inc | 2.25 | 2,232,680 | +27.3 | 03/31/2026 |
| Blair William & Co | 1.78 | 1,769,432 | +165.8 | 06/30/2026 |
| American Century Companies Inc | 1.60 | 1,587,196 | +29.9 | 06/30/2026 |
| Amvescap Plc. | 1.60 | 1,585,003 | +23.9 | 03/31/2026 |
Funds
| Name | Stake (%) | Shares | Change (%) | Date |
|---|---|---|---|---|
| Vanguard MStar Total Stk Mkt Idx Invest | 2.74 | 2,720,399 | +0.3 | 07/31/2026 |
| iShares Russell 2000 ETF | 1.98 | 1,964,303 | -0.6 | 08/31/2026 |
| Vanguard Small Cap Index | 1.98 | 1,962,166 | +0.1 | 07/31/2026 |
Largest reported positions according to regulatory filings; stake as a percentage of shares outstanding, change versus the previous filing. Source: fundamentals data.
Insider holdings
| Person | Role | Shares | Value | As of | Type |
|---|---|---|---|---|---|
| Gallagher Thomas P. | Chairman & CEO | 2,209,817 | 83,310,101 $ | Sep 3, 2026 | both |
| Comly Barbara J. | EVP, GC & Corporate Secretary | 839,564 | 31,651,563 $ | Sep 2, 2026 | direct |
| Schafer Douglas M. JR | EVP and CIO | 387,414 | 14,605,508 $ | Sep 2, 2026 | direct |
| Brown Shelly | EVP, Chief Strategy Officer | 337,707 | 12,731,554 $ | Sep 11, 2026 | direct |
| Teekell Judson Gray | Director | 150,251 | 5,664,463 $ | Sep 2, 2026 | both |
| Eckert Kurt M. | Director | 149,612 | 5,640,372 $ | Aug 4, 2026 | direct |
| Deitzel Edward | EVP, CRO, CCO MIAX Exchanges | 119,601 | 4,508,958 $ | Sep 3, 2026 | direct |
| Schwarzkopf Cynthia | Director | 88,545 | 3,338,147 $ | Aug 17, 2026 | direct |
| Emmons Lance | EVP and CFO | 86,538 | 3,262,483 $ | Aug 17, 2026 | direct |
| Jayabalan Harish | EVP, CISO and CRO | 78,065 | 2,943,051 $ | Aug 4, 2026 | direct |
| Brown David A | Director | 7,066 | 266,388 $ | Jul 8, 2026 | direct |
Holdings as of each person's most recent SEC Form 4 filing — excluding options and RSUs, which are not shares yet. Holdings may have changed between two filings.
Insiders
Insider Transactions
| Date | Person | Role | Type | Shares | Price | Value |
|---|---|---|---|---|---|---|
| Sep 11, 2026 | Brown Shelly | EVP, Chief Strategy Officer | Other | 16,283 | 42.54 | 692,679 |
| Sep 3, 2026 | Deitzel Edward | EVP, CRO, CCO MIAX Exchanges | Sell | 11,000 | 42.21 | 464,310 |
| Sep 3, 2026 | Deitzel Edward | EVP, CRO, CCO MIAX Exchanges | Other | 11,000 | 12.00 | 132,000 |
| Sep 3, 2026 | Gallagher Thomas P. | Chairman & CEO | Other | 4,464 | 22.40 | 99,994 |
| Sep 3, 2026 | Gallagher Thomas P. | Chairman & CEO | Other | 13,140 | 15.22 | 199,991 |
| Sep 3, 2026 | Gallagher Thomas P. | Chairman & CEO | Other | 8,333 | 12.00 | 99,996 |
| Sep 3, 2026 | Gallagher Thomas P. | Chairman & CEO | Other | 16,666 | 12.00 | 199,992 |
| Sep 3, 2026 | Gallagher Thomas P. | Chairman & CEO | Sell | 47,000 | 42.43 | 1,994,210 |
| Sep 3, 2026 | Gallagher Thomas P. | Chairman & CEO | Other | 47,000 | 12.00 | 564,000 |
| Sep 2, 2026 | Comly Barbara J. | EVP, GC & Corporate Secretary | Sell | 44,445 | 40.49 | 1,799,578 |
| Sep 2, 2026 | Comly Barbara J. | EVP, GC & Corporate Secretary | Other | 44,445 | 12.00 | 533,340 |
| Sep 2, 2026 | Schafer Douglas M. JR | EVP and CIO | Sell | 48,000 | 40.48 | 1,943,040 |
| Sep 2, 2026 | Schafer Douglas M. JR | EVP and CIO | Other | 4,666 | 12.00 | 55,992 |
| Sep 2, 2026 | Schafer Douglas M. JR | EVP and CIO | Other | 43,334 | 12.00 | 520,008 |
| Sep 2, 2026 | Teekell Judson Gray | Director | Sell | 3,000 | 40.89 | 122,670 |
| Sep 2, 2026 | Teekell Judson Gray | Director | Sell | 5,545 | 41.58 | 230,561 |
| Aug 19, 2026 | Gallagher Thomas P. | Chairman & CEO | Sell | 149,700 | 41.13 | 6,157,161 |
| Aug 18, 2026 | Comly Barbara J. | EVP, GC & Corporate Secretary | Other | 43,420 | 42.41 | 1,841,442 |
| Aug 18, 2026 | Gallagher Thomas P. | Chairman & CEO | Other | 150,300 | 42.41 | 6,374,223 |
| Aug 17, 2026 | Schwarzkopf Cynthia | Director | Sell | 5,000 | 42.85 | 214,250 |
| Aug 17, 2026 | Schwarzkopf Cynthia | Director | Other | 5,000 | 12.00 | 60,000 |
| Aug 17, 2026 | Emmons Lance | EVP and CFO | Sell | 35,000 | 42.83 | 1,499,050 |
| Aug 4, 2026 | Comly Barbara J. | EVP, GC & Corporate Secretary | Sell | 44,445 | 45.69 | 2,030,692 |
| Aug 4, 2026 | Comly Barbara J. | EVP, GC & Corporate Secretary | Other | 44,445 | 12.00 | 533,340 |
| Aug 4, 2026 | Eckert Kurt M. | Director | Sell | 1,063 | 45.80 | 48,685 |
| Aug 4, 2026 | Eckert Kurt M. | Director | Other | 1,063 | 12.00 | 12,756 |
| Aug 4, 2026 | Deitzel Edward | EVP, CRO, CCO MIAX Exchanges | Sell | 11,000 | 45.78 | 503,580 |
| Aug 4, 2026 | Deitzel Edward | EVP, CRO, CCO MIAX Exchanges | Other | 11,000 | 12.00 | 132,000 |
| Aug 4, 2026 | Jayabalan Harish | EVP, CISO and CRO | Sell | 20,000 | 45.90 | 918,000 |
| Aug 4, 2026 | Jayabalan Harish | EVP, CISO and CRO | Other | 5,832 | 15.22 | 88,763 |
| Aug 4, 2026 | Jayabalan Harish | EVP, CISO and CRO | Other | 14,168 | 12.00 | 170,016 |
| Aug 4, 2026 | Gallagher Thomas P. | Chairman & CEO | Sell | 48,334 | 45.69 | 2,208,380 |
| Aug 4, 2026 | Gallagher Thomas P. | Chairman & CEO | Other | 48,334 | 12.00 | 580,008 |
| Aug 4, 2026 | Schafer Douglas M. JR | EVP and CIO | Sell | 48,000 | 45.71 | 2,194,080 |
| Aug 4, 2026 | Schafer Douglas M. JR | EVP and CIO | Other | 48,000 | 12.00 | 576,000 |
| Aug 4, 2026 | Teekell Judson Gray | Director | Sell | 3,000 | 45.79 | 137,370 |
| Jul 15, 2026 | Schwarzkopf Cynthia | Director | Sell | 5,000 | 42.00 | 210,000 |
| Jul 15, 2026 | Schwarzkopf Cynthia | Director | Other | 5,000 | 12.00 | 60,000 |
| Jul 13, 2026 | Comly Barbara J. | EVP, GC & Corporate Secretary | Sell | 28,000 | 41.98 | 1,175,440 |
| Jul 13, 2026 | Comly Barbara J. | EVP, GC & Corporate Secretary | Other | 28,000 | 12.00 | 336,000 |
| Jul 13, 2026 | Gallagher Thomas P. | Chairman & CEO | Sell | 70,000 | 42.52 | 2,976,400 |
| Jul 13, 2026 | Gallagher Thomas P. | Chairman & CEO | Other | 70,000 | 12.00 | 840,000 |
| Jul 8, 2026 | Brown David A | Director | Other | 171 | 43.72 | 7,476 |
Reportable transactions by officers and major shareholders from SEC Form 4 filings. "Other" includes things like stock grants and option exercises without a buy/sell character. View all insider transactions →
Data as of: September 17, 2026 · Source: fundamental data & SEC filings (annual and quarterly reports, 10-K/10-Q)
Note: pure fact-based analysis, not investment advice and not a solicitation to buy or sell. All figures without guarantee.