Blair William & Co. IL Takes Position in Miami International Holdings, Inc.

The investment firm purchased over 360,000 shares of the options exchange operator.

Published on Mar. 9, 2026

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Blair William & Co. IL, an investment management firm, purchased a new position in Miami International Holdings, Inc. (NYSE:MIAX) during the third quarter of 2025. The firm acquired 363,765 shares of the company's stock, valued at approximately $14.6 million, giving them a 0.45% ownership stake in Miami International.

Why it matters

This investment highlights the growing interest and confidence in Miami International Holdings, which operates the Miami International Securities Exchange (MIAX). As a major player in the options trading market, Miami International's performance is closely watched by investors and analysts.

The details

According to the filing with the Securities and Exchange Commission, Blair William & Co. IL purchased the 363,765 shares of Miami International Holdings in the third quarter of 2025. This new position represents 0.45% ownership of the company by the investment firm.

  • Blair William & Co. IL purchased the shares in the third quarter of 2025.

The players

Blair William & Co. IL

An investment management firm that purchased a new position in Miami International Holdings, Inc.

Miami International Holdings, Inc.

A U.S. exchange holding company that operates electronic trading venues and provides market infrastructure for listed options and related products.

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The takeaway

This investment by a prominent firm like Blair William & Co. IL suggests growing confidence in Miami International Holdings' ability to capitalize on the increasing demand for options trading and electronic exchange services.