The Dollar-Mark Axis. — Over the last two decades, most European currencies have tended to weaken against the mark as the latter strengthened against the dollar. Moreover, the strength of the response of European cross rates has tended to remain in the same order over time. The paper first sets out the stylised facts of this phenomenon, referred to as the dollar-mark axis, and then tries to identify its determinants. In addition to exchange rate policy, the paper examines the correlation of cyclical fluctuations and trade links and the bias of international investors in the currency composition of their portfolios.