Shares in the The Chicago Board of Trade, the second largest derivatives exchange in the US, rocketed by over 56% during their first half hour of trading today as investors shrugged off fears that sentiment might be hit from the scandal surrounding one of its five biggest clients, futures broker Refco.

Yesterday CBOT's flotation priced higher than expected at $54. By 14:30 GMT today - 30 minutes after it started trading on the New York Stock Exchange - the exchange's shares hit $85.