Soft exchange rate bands and speculative attacks: theory, and evidence from the ERM since August 1993

We present a model of a "soft" exchange rate target zone and interpret it a s a stylized description of the post-august 1993 ERM. Our central bank targ ets a moving average of the current and past exchange rates, rather than th e exchange rate's current level, thus allowing the rate to move within wide margins in the short run, but within narrow margins in the long run. For r ealistic parameters, soft target zones are significantly less vulnerable to speculative attacks than "hard" target zones. These predictions are consis tent with the ERM's experience and the abatement of speculative pressure in European markets since the bands' widening in 1993. (C) 1999 Elsevier Scie nce B.V. All rights reserved.