Robert Greifeld, the chief executive of Nasdaq and the mastermind behind its merger with European group OMX a month ago, has added to calls for regulatory reform, arguing exchanges regulated in the US are at a disadvantage.

Greifeld, who spearheaded two failed bids to buy the London Stock Exchange in 2006 and 2007, said US rules regulated by the Securities and Exchanges Commission are unwieldy and US exchanges should be given more flexibility.