States and Japan. There is, however, a trade-off between volatility and level. While the aggregate EU data on GDP growth from 1986 to 1995 has been approximately equal to that of the United States and Japan, EU inflation and interest rates have been higher than those in either the United States or Japan. Against this background, the main uncertainty in moving to a single monetary policy is that there is no guarantee that the stability of the money demand function would continue after EMU. If the relationship was more unstable, the gains in macroeconomic stability