柯南（Peter Kenen）在20世纪60年代末指出，如果没有汇率变动作为冲击吸收器，货币联盟就需要财政转移来作为分担风险的办法。
Peter Kenen argued in the late 1960’s that without exchange-rate movements as a shock absorber, a currency union requires fiscal transfers as a way to share risk.