A unified approach to determinacy conditions with regime switching

Abstract

The conditions that ensure the existence of a unique stable equilibrium — determinacy conditions — for rational expectations models with Markov switching depend on the stability concept, contrasting with standard linear rational expectations models. In this paper, we offer a unified framework for the two commonly used stability concepts: boundedness and mean-square stability. We derive determinacy conditions for both concepts based on simple metrics. Qualitatively, we show that mean-square stable solutions are always at least as many as bounded solutions. We then apply and discuss our results in two monetary models.