The Intercontinental Exchange, the energy derivatives market operator, has offered the Chicago Board of Trade almost $1bn (€756m) more than a rival bid from the Chicago Mercantile Exchange, in an attempt to derail the agreed merger due to be voted on by shareholders next month.

ICE, headquartered in Atlanta, today offered $9.9bn (€7.5bn) to merge with the CBOT in a deal it said "would create the world's most comprehensive derivatives exchange". It will issue 1.42 of its own shares for each CBOT share.