The owner of the Bermuda Stock Exchange, Miami International Holdings Inc, saw a dramatic rise in share price after its initial public offering in New York, which valued the regulated financial markets operator at about $2.5 billion.

The IPO of 15 million shares of its common stock at a price to the public of $23 a share, was $2 above the high end of the expected price range.

The shares of common stock began trading on the New York Stock Exchange under the ticker symbol "MIAX” today.

The offering was expected to close tomorrow, subject to customary closing conditions. MIH also has granted the underwriters a 30-day option to purchase up to an additional 2,250,000 shares of common stock at the initial public offering price, less underwriting discounts and commissions.

Thomas Gallagher, chairman and CEO of MIAX, said in a Reuters interview: “We thought now is a good time [for us to go public] because of the macroeconomic climate. I also thought in mid-August there wouldn't be as much going on in the capital markets with respect to IPOs, and we could get the attention.”

Miami International Holdings, the parent holding company of MIAX, acquired 100 per cent ownership of the Bermuda Stock Exchange in December 2020.

Mr Gallagher said at the time: “We have long held that the Bermuda Government's commitment to fintech regulation and the country's established [insurance and] reinsurance market make the BSX and Bermuda key components of MIH's global ambitions.”

MIH had previously taken majority ownership a year before.

Reuters said the Princeton, New Jersey-based company sold 15 million shares above the marketed range of $19 to $21 apiece to raise $345 million, making it one of the biggest share sales of a US bourse operator.

The news agency added that exchanges have thrived this year as heightened market volatility fuelled record trading volumes and boosted profits.

Matt Kennedy, senior strategist at the IPO-focused research and exchange-traded funds provider Renaissance Capital, said: “It’s a niche area, but it’s one investors are comfortable with. MIAX is clearly riding some multiyear tailwinds in the options space.”

Shares of MIAX, which has been attempting to go public since 2022, when it first filed confidentially for its flotation, opened for trading at $31.65 apiece, above the $23 IPO price.

MIAX, which was cofounded by Mr Gallagher, was launched in 2007 after a wave of consolidation among equity and options exchanges.

MIAX operates nine securities and derivatives exchanges and the majority of its revenues are generated from options trading. The US options market has witnessed explosive growth since the Covid-19 pandemic and the meme-stock frenzy of 2021.

The company launched its first options exchange in 2012 and has gained market share from rivals over the past decade.

In the first half of 2025, it had a 16 per cent market share in the US options industry, behind only the New York Stock Exchange, Nasdaq and the Chicago Board Options Exchange, according to the Options Clearing Corporation.