Increasing Returns and the Design of Interest Rate Rules

We introduce increasing returns to scale into an otherwise standard New Keynesian model with capital, and study the determinacy and E-stability of Taylor-type interest rate rules. With very mild increasing returns supported by empirical research, the conventional wisdom regarding the design of interest rate rules can be overturned. In particular, the "Taylor principle" no longer guarantees either determinacy or E-stability of the rational expectations equilibrium.