The Euro could displace the dollar as the major international currency outside the United States and Asia if financial markets integrate rapidly enough, researchers say. Economists Richard Portes of London Business School and Helene Rey of the London School of Economics outline their arguments in a book, Prospects and Challenges for the Euro. They cite a possible 0.5 per cent annual gain in Europe's gross domestic product, with a similar loss for the US and a shift from dollar- to euro-denominated assets.