OPTIMAL FISCAL POLICY IN A BUSINESS CYCLE MODEL: ALTERNATIVE IDENTIFICATIONS OF THE OPTIMAL EXPOST CAPITAL INCOME TAX RATES

This paper deals with the indeterminacy of optimal fiscal policy treated by Zhu (1992) and Chari, Christiano and Kehoe (1994). These authors identify the optimal fiscal policy restricting the debt return to be uncontingent to the state of nature. In this paper we use other kind of restrictions in order to identify the optimal fiscal policy. Using the solution method proposed by Sims (1998), we can select an equilibrium by enforcing a stable path for the bonds allocation, to identify all the fiscal policy variables contingent to the state of nature. We also use a decomposition of the expectational terms that allow us to obtain the ex-ante capital income tax rate in order to be compared with the ex-post (contingent) tax rate. We can demonstrate that the risk aversion changes the relationship between the expectational errors of the private agents and the sources of fluctuations. The numerical simulation provides some different results: the optimal tax rate on capital incom e is constant, instead of the very volatile tax rate obtained by Chari, Christiano and Kehoe (1994). This property remains unaltered when we use alternative restrictions (exogenous debt path and exogenous expectational errors) to identify the contingent optimal fiscal policy.