The world’s major economies show stable economic momentum but the euro zone continues to lose steam, notably in Germany and Italy, while Japan and Britain may be faltering too, the OECD said on Wednesday. The prediction, based on what the Paris-based Organisation for Economic Co-operation and Development calls a leading indicator to flag turning points in the outlook, showed a stable 100.4 index reading for the OECD grouping of economies as a whole versus a previous monthly survey.