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Fiscal Sustainability in a New Keynesian Model

  • Campbell Leith

    (University of Glasgow)

  • Simon Wren-lewis

    (University of Exeter)

There has been a wealth of recent work deriving optimal monetary policy utilising New Neo-Classical Synthesis (NNCS) models based on nominal inertia. Such models typically abstract from the impact of monetary policy on the government’s finances, by assuming that consumers are infinitely-lived and taxes are lump-sum such that Ricardian Equivalence holds. In this paper, in the context of a sticky-price NNCS model, we assume that the government must adjust spending and/or distortionary taxation to satisfy its intertemporal budget constraint. We then consider optimal monetary and fiscal policies under discretion and commitment in the face of technology, preference and cost-push shocks. We find that the optimal precommitment policy implies a random walk in the steady-state level of debt, generalising earlier results that involved only a single fiscal instrument. In the case of negative fiscal shocks this implies permanently higher taxation and lower output and government spending to support the new steady-state debt stock, but the optimal combination of these variables will ensure a zero rate of inflation under commitment. We also find that the time-inconsistency in the optimal precommitment policy is such that governments are tempted, given inflationary expectations, to raise taxation to reduce the ultimate debt burden they need to service. Since taxation is a distortionary labour income tax, this aggressive raising of taxation raises firms’ marginal costs and fuels inflation. We show that this temptation is only eliminated if following shocks, the new steady-state debt is equal to the original, first-best, debt level. This implies that under discretionary policy the random walk result is overturned: debt will always be returned to this initial steady-state even although there is no explicit debt target in the government’s objective function. In a series of numerical simulations we show that the welfare consequences of introducing debt are negligible for precommitment policies, but can be significant for discretionary policy.

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Paper provided by ESRC World Economy and Finance Research Programme, Birkbeck, University of London in its series WEF Working Papers with number 0006.

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Date of creation: Mar 2006
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Handle: RePEc:wef:wpaper:0006
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  1. P. Benigno & M. Woodford, 2003. "Optimal monetary and fiscal policy: a linear-quadratic approach," Proceedings, Board of Governors of the Federal Reserve System (U.S.).
  2. Obstfeld, Maurice, 1991. "Dynamic Seigniorage Theory: An Exploration," CEPR Discussion Papers 519, C.E.P.R. Discussion Papers.
  3. Bernheim, B Douglas, 1991. "Optimal Fiscal and Monetary Policy: Some Recent Results," Journal of Money, Credit and Banking, Blackwell Publishing, vol. 23(3), pages 540-42, August.
  4. Lombardo, Giovanni & Sutherland, Alan, 2004. "Monetary and fiscal interactions in open economies," Journal of Macroeconomics, Elsevier, vol. 26(2), pages 319-347, June.
  5. Barro, Robert J, 1979. "On the Determination of the Public Debt," Journal of Political Economy, University of Chicago Press, vol. 87(5), pages 940-71, October.
  6. Campbell leith & Jim Malley, 2002. "Estimated General Equilibrium Models for the Evaluation of Monetary Policy in the US and Europe," Working Papers 2001_16, Business School - Economics, University of Glasgow.
  7. V. V. Chari & Lawrence J. Christiano & Patrick J. Kehoe, 1991. "Optimal fiscal and monetary policy: some recent results," Staff Report 147, Federal Reserve Bank of Minneapolis.
  8. Leith, Campbell & Wren-Lewis, Simon, 2006. "Compatibility between monetary and fiscal policy under EMU," European Economic Review, Elsevier, vol. 50(6), pages 1529-1556, August.
  9. Ellison, Martin & Rankin, Neil, 2007. "Optimal monetary policy when lump-sum taxes are unavailable: A reconsideration of the outcomes under commitment and discretion," Journal of Economic Dynamics and Control, Elsevier, vol. 31(1), pages 219-243, January.
  10. Peter N. Ireland, 2004. "Technology Shocks in the New Keynesian Model," The Review of Economics and Statistics, MIT Press, vol. 86(4), pages 923-936, November.
  11. Soderlind, Paul, 1999. "Solution and estimation of RE macromodels with optimal policy," European Economic Review, Elsevier, vol. 43(4-6), pages 813-823, April.
  12. Smets, Frank & Wouters, Raf, 2004. "Comparing shocks and frictions in US and euro area business cycles: a Bayesian DSGE approach," Working Paper Series 0391, European Central Bank.
  13. Calvo, Guillermo A., 1983. "Staggered prices in a utility-maximizing framework," Journal of Monetary Economics, Elsevier, vol. 12(3), pages 383-398, September.
  14. Beetsma, Roel M. W. J. & Jensen, Henrik, 2004. "Mark-up fluctuations and fiscal policy stabilization in a monetary union," Journal of Macroeconomics, Elsevier, vol. 26(2), pages 357-376, June.
  15. Campbell Leith & Simon Wren-lewis, 2006. "The Costs of Fiscal Inflexibility," WEF Working Papers 0005, ESRC World Economy and Finance Research Programme, Birkbeck, University of London.
  16. Obstfeld, Maurice, 1997. "Dynamic Seigniorage Theory," Macroeconomic Dynamics, Cambridge University Press, vol. 1(03), pages 588-614, September.
  17. Leith, Campbell & Wren-Lewis, Simon, 2000. "Interactions between Monetary and Fiscal Policy Rules," Economic Journal, Royal Economic Society, vol. 110(462), pages C93-108, March.
  18. Richard Clarida & Jordi Gali & Mark Gertler, 2001. "Optimal Monetary Policy in Open versus Closed Economies: An Integrated Approach," American Economic Review, American Economic Association, vol. 91(2), pages 248-252, May.
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