CMC, the UK-based online currency and derivatives broker, was last night marketing its initial public offering at nearly a quarter less than planned and faced the possibility of postponing the deal altogether, according to market sources.

The bookrunners on the deal, Deutsche Bank and JP Morgan Cazenove, have been marketing the float with a price range of 630p to 760p, which would value the firm at £630m (€923.9m) to £760m.