TMX Group to take 59% of new US$2.3B options group MEMX

Toronto-based TMX Group has agreed to make a strategic investment in US exchange operator MEMX and combine it with equity options market BOX , creating a consolidated US exchange group valued at about US$2.3 billion. TMX will hold roughly 59% of the combined business, funded partly by an equity investment of about US$800 million.

MEMX is an exchange operator and market technology provider, while BOX runs a US equity options market with both electronic and floor-based trading. TMX provides data, listing, trading, and clearing services globally.

The combined company will hold three exchange licenses, operate three US listed options exchanges plus an equities exchange, and represent roughly 10% of US listed options volume. Jonathan Kellner, CEO of MEMX, will lead the new group and will continue to operate it independently.

MEMX and BOX delivered combined revenue of about US$280 million and adjusted EBITDA of about US$134 million in 2025. Beyond TMX's US$800 million, the deal includes a rollover of TMX's existing BOX stake, committed rollovers from MEMX and BOX investors, and a new financial partner, Markets Infrastructure Partners.

"TMX is a long-standing investor in the US options market, and today we are pleased to announce a significant increase in our stake," said John McKenzie, CEO of TMX Group. The deal grants TMX call rights and minority holders put rights, starting three years after close.

Kellner said combining BOX's electronic and open outcry trading with MEMX's price-time and pro-rata exchanges provides "enhanced customer functionality and the ability to compete across all of the US options exchange models."

The tie-up reflects continued consolidation among US market infrastructure players, with existing MEMX backers — including Chicago Trading Company , IMC , Jane Street, Morgan Stanley , Optiver, Schwab, and Virtu — rolling equity into a larger, multi-asset operator positioned to compete across both options and equities.