This thesis analyzes the determinants from which countries and regions adapt their exported product portfolios while facing a joint intensification of world trade flows and international competition. In the unprecedented context of current globalization, the emergence of new competitors and their ability to quickly reposition themselves on increasingly sophisticated ranges of products induces a reshape of the world market, an intensification of the competitive pressure and a growing interdependence of each other. Even though developed countries still occupy a prominent place in the international trade, they are henceforth challenged by the rise of emerging countries. This leads us to discuss strategies for repositioning export portfolios of...