Nasdaq has struck the latest blow in its battle with NYSE Euronext by launching a product that takes advantage of sweeping new trading rules in the US - which NYSE sought to delay because its systems were insufficiently prepared - just one day after its main rival cut fees to win back market share from Nasdaq.

Nasdaq has boosted its online service by releasing a feature that enables institutional investors to calculate the cost of trading before generating orders, a key requirement after the US regulator introduced new laws designed to lower the cost of trading US shares six months ago.