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Who owns Miami International Holdings (MIAX) stock

195 funds reported Miami International Holdings (MIAX) shares in their latest 13F filings, worth $2.7B in all. The largest holder is Horizon Kinetics Asset Management LLC ($291M). Last quarter 130 funds added to their stakes and 78 cut them. Members of Congress and other officials disclosed 1 trade (1 buys, 0 sales).

Largest holders of MIAX (13F)Largest holders of MIAX (13F)Horizon Kinetics Asset Management…$291MBlackRock$188MT. Rowe Price Investment Manageme…$187MVanguard Portfolio Management LLC$141MSusquehanna International Group, …$125MVanguard Capital Management LLC$118MVanguard Group$85.6MInvesco$75.1MJ Digital 6 LLC$67.2MBlair William$65.8M

Largest holders (13F)

FundSharesValueChangeQuarter
Horizon Kinetics Asset Management LLC7,842,173$291Mincrease2026-06-30
BlackRock5,071,754$188Mincrease2026-06-30
T. Rowe Price Investment Management5,032,970$187Mincrease2026-06-30
Vanguard Portfolio Management LLC3,786,418$141Mincrease2026-06-30
Susquehanna International Group, LLP3,355,043$125Mincrease2026-06-30
Vanguard Capital Management LLC3,165,686$118Mincrease2026-06-30
Vanguard Group1,928,286$85.6Mincrease2025-12-31
Invesco2,020,650$75.1Mincrease2026-06-30
J Digital 6 LLC1,807,234$67.2Mnew2026-06-30
Blair William1,769,432$65.8Mincrease2026-06-30
Balyasny Asset Management L.P.1,682,924$62.5Mnew2026-06-30
American Century Companies1,587,196$59.0Mincrease2026-06-30
State Street1,432,894$53.2Mincrease2026-06-30
Geode Capital Management, LLC1,395,680$51.9Mincrease2026-06-30
Adage Capital Partners GP, L.L.C.1,143,920$42.5Mdecrease2026-06-30

Trades by Congress and other officials

DateWhoTradeAmount
2026-03-20Gilbert Cisnerospurchase$15K–$50K

Miami International Holdings' latest quarter

Miami International Holdings, Q3 2026: revenue $376M (+11% year over year), operating margin 12.5%, net earnings $52.5M, operating cash flow $23.1M. The chart follows the revenue to costs, profit and cash.

Questions

Who owns the most MIAX stock?

By the latest 13F filings: Horizon Kinetics Asset Management LLC ($291M); BlackRock ($188M); T. Rowe Price Investment Management ($187M); Vanguard Portfolio Management LLC ($141M); Susquehanna International Group, LLP ($125M).

Has Congress traded MIAX stock?

Officials disclosed 1 trade on file: 1 buys and 0 sales. The latest: Gilbert Cisneros, purchase on 2026-03-20.

What is the short interest in MIAX?

7,967,675 shares were sold short at the 2026-10-15 settlement, -10.28% of the float.

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Updated Nov 8, 2026. Read automatically from SEC filings and public data; errors are possible. Not investment advice.