This paper investigates the implications of the size of budget deficit in the open economy under perfect mobility of capital. For that purpose we construct a general equilibrium model with consumers maximizing the discounted utility of consumption, and firms maximizing profits. Government sets the size of the deficit relative to GDP and controls the structure of public debt. Using standard methods of optimal control theory we solve the model, i.e. we find explicit formulas for all trajectories and the level of welfare. Finally, we show that the higher the deficit-to-GDP ratio, the lower the welfare of consumers. Similarly, welfare increases with the share of foreign creditors in public debt.

In this paper we develop an open-economy endogenous growth model to examine the influence of fiscal policy on the economy in the long run. We allow for public deficit and 5 types of taxes. One of the novel features is separate treatment of interest rates on public and private debt, both of which are linear functions of appropriate debt-to-GDP ratios. Two extreme situations are analyzed: a model of “decentralized economy”, where economic agents do not take into account any externalities, and a model of “benevolent social planner”. We derive the rules of optimal fiscal policy that induce economic agents to internalize all externalities. Theoretical results are illustrated with an empirical analysis for Poland. The optimal values of several fiscal policy instruments for Poland are calculated.

This paper investigates the linkages between economic growth and fiscal policy under perfect capital mobility. The model incorporates wide range of fiscal policy instruments: the budget deficit, the structure of public debt, public expenditures on education, public consumption, and four tax rates. We prove that two tax rates - on consumption and interest on government bonds held by domestic lenders - are neutral for economic growth: both for the balanced growth path (BGP), and for transitory dynamics. All other parameters of fiscal policy are not neutral. Theoretical results are illustrated with an empirical analysis for Poland based on post-global financial crisis data for the Polish economy (2009-2018). Numerical simulations show that if fiscal policy remains unchanged, Polish economy will converge to the BGP with GDP growing at 2.3%. The best way to accelerate growth is to increase public investment in education. The other budgetary policy instruments are less effective in shaping economic growth.