NYSE Euronext, the world's biggest stock exchange, has fired the latest salvo in its battle with Nasdaq, by improving the rebate it awards for trading its main rival's stock just a week after Nasdaq changed its prices.

NYSE Euronext, the transatlantic exchange group, has pledged to increase the rebate it offers brokers trading over 30 million Nasdaq-listed shares a day in any month to $0.0024 a share, from a previous rate of $0.0020 a share, effective January 2 2008.