The success of the deal surprised few; Ice had already doubled the size of the offering in response to investor demand.

Ice sold 2.5 million shares, the proceeds of which will be used to clear all $13 million of the exchange’s debt and for general corporate purposes. Ice’s existing shareholders are selling a further 13.5 million shares.

“Ice’s listing is a significant milestone for the company and the energy-trading community,” said chairman and chief executive Jeffrey Sprecher. “We take great