Interest rate rules and multiple equilibria in the small open economy

In a small open economy model with traded and non-traded goods this paper characterizes conditions under which interest rate rules induce aggregate instability by generating multiple equilibria. These conditions depend not only on how aggressively the rule responds to inflation, but also on the measure of inflation to which the government responds, on the degree of openness of the economy and on the degree of exchange rate pass-through. As an important policy implication, this paper finds that to avoid aggregate instability in the economy the government should implement an aggressive rule with respect to the inflation rate of the sector that has sticky prices. That is the non-traded goods inflation rate. As a by-product of this analysis, it is shown that \"fear-of-floating\" governments that follow a rule that responds to both the CPI-inflation rate and the nominal depreciation rate or governments that implement \"super-inertial\" interest rate smoothing rules may actually induce multiple equilibria in their economies. This paper also shows that for forward-looking rules, the determinacy of equilibrium conditions depends not only on the degree of openness of the economy but also on the weight that the government puts on expected future CPI-inflation rates. In fact rules that are \"excessively\" forward-looking always lead to multiple equilibria.