The dynamics of interest rate and tax rules in a stochastic model

A simple stochastic equilibrium structure is used to study the implications of monetary and fiscal policy interactions for government intertemporal budget balance. Existence and uniqueness of monetary equilibria are shown to depend on parameters of policy rules. The paper derives closed form solutions for equilibrium inflation and real debt as functions of policy parameters and policy shocks and obtains conditions under which the usual tests that deficits Granger-cause money creation will successfully uncover evidence of monetized deficits. In addition, equilibria are studied in which private agents today know tomorrow's taxes exactly. Coupling this informational assumption with a monetary policy that pegs the nominal interest rate reverses the usual Granger-causal ordering between deficits and monetization, so that money growth (or inflation) may predict higher deficits. This implies that empirical work designed to detect that deficits have been monetized by testing whether deficits Granger-cause money creation, may fail to uncover the monetization.