Miami International Stock Is Up Big Since Its Debut. Is It a Buy as Insiders Trim?
Key Points
Teekell sold 3,000 shares for a total value of $137,370 on August 4.
The disposition involved shares held directly by the insider and did not include any indirect ownership entities.
The sale was executed under a Rule 10b5-1 trading plan adopted on December 17, 2025.
Judson Gray Teekell, a director at Miami International Holdings, Inc. (NYSE:MIAX), sold 3,000 shares of common stock on August 4, according to an SEC Form 4 filing.
Transaction summary
| Metric | Value |
|---|---|
| Transaction value | $137,370 |
| Shares sold | 3,000 |
| Post-transaction shares (directly held) | 72,251 |
| Post-transaction value | $3.28 million |
Transaction value based on SEC Form 4 weighted average sale price ($45.79); post-transaction value based on the August 4 market close ($45.34).
Key questions
- What was the execution price range for this transaction?
The 3,000 shares were sold in multiple trades throughout the day on August 4, at prices ranging from $45.13 to $46.56, resulting in a weighted average execution price of $45.79 per share. - How does this sale impact the director's remaining equity position?
Following the disposition, Teekell retains 72,251 shares of common stock directly. - What was the role of the Rule 10b5-1 plan in this trade?
The sale was conducted under a trading plan established more than seven months prior, on December 17, 2025, a mechanism that allows insiders to schedule stock sales in advance to manage liquidity according to regulatory safe harbor guidelines. - How does the current market price compare to the transaction date valuation?
The shares were priced at $45.96 as of the August 5 market close, slightly higher than the $45.34 valuation price recorded on the date of the transaction.
Company Overview
| Metric | Value |
|---|---|
| Share Price (as of market close 2026-08-05) | $45.96 |
| Market Capitalization | $4.4 billion |
| Revenue (TTM) | $1.5 billion |
| Net Income (TTM) | $142.3 million |
Company Snapshot
- Miami International Holdings operates a diversified marketplace ecosystem that provides trading venues for options, futures, and cash equities, generating revenue through transaction fees, market data services, and technology licensing across its MIAX Options, MIAX Pearl, MIAX Emerald, MIAX Sapphire, MIAX Pearl Equities, and MIAX Futures platforms.
- The company generates revenue through a transaction-based model, capturing fees from trading volume across its multiple exchange platforms, supplemented by ancillary revenue streams, including market data dissemination, connectivity services, and regulatory fees.
- The company serves institutional investors, retail traders, market makers, and broker-dealers seeking access to diversified trading venues for options, equities, and futures products in the United States capital markets.
Miami International Holdings is a mid-cap financial services infrastructure provider with a $4.4 billion market capitalization that operates as a critical marketplace operator in U.S. capital markets. The company's diversified platform architecture across options, equities, and futures segments positions it to capture trading volume across multiple asset classes. MIAX maintains competitive advantages through its technology infrastructure, regulatory approvals across multiple asset classes, and established relationships with market participants seeking alternative execution venues.
What this transaction means for investors
A director selling a small block on a plan set last December is the mildest kind of insider filing there is, and Teekell's fits the pattern of several MIAX insiders trimming in the same window, with none of it being discretionary. And unlike the executives who exercised old options, he simply sold shares he already held, and kept more than 72,000 of them, so the vast majority of his stake remains intact.
The company behind the filing is executing well. Since debuting on the public market in August 2025, shares have skyrocketed over 80% from their offering price, and it just grew second-quarter net revenue 35% to $141 million as options volume rose 25% to 11 million contracts a day, with margins widening past 54% and a long-running Nasdaq lawsuit settled and paid. CEO Thomas Gallagher said the "model's operating leverage drove record margins."
The headwinds are real, since the elevated options volume that drove the quarter is expected to cool, and the newer futures business still runs at a loss, but the options franchise at the core is growing and getting more profitable, which is why a director trimming on schedule reads as routine rather than a warning.
Jonathan Ponciano has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends Miami International. The Motley Fool has a disclosure policy.