Fiscal sustainability

Fiscal Sustainability: A Primer

Nobody likes taxes, so public spending frequently exceeds revenues, leading governments to borrow. These budget deficits are a flow that add to the stock of debt. Since the Great Financial Crisis of 2007-2009, public debt in a number of advanced economies has surged. In the United States. the Congressional Budget Office (CBO) recently projected that―in the absence of policy changes―federal debt held by the public is headed for record highs (as a ratio to GDP) in coming decades.

Importantly, there is a real (inflation-adjusted) limit to how much public debt a government can issue (see Sargent and Wallace). Beyond that limit, the consequences are outright default or, if the debt is in domestic currency bonds that the central bank acquires, inflation that erodes its real value leading to a partial default.

Ultimately, debt sustainability requires that a country’s ratio of public debt to GDP stabilize. Otherwise, debt eventually will rise above the real limit and trigger default or inflation. In this note, we derive and interpret a simple debt-sustainability condition. The condition states that the government primary surplus―the excess of government revenues over noninterest spending—must be at least as large as the stock of outstanding sovereign debt times the difference between the nominal interest rate the government has to pay and the rate of growth of nominal GDP. If it is not, then the ratio of debt to GDP will explode….

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Italeave: Mother of all financial crises

After years of calm, fears of a currency redenomination—prompted by the attitudes toward monetary union of Italy’s now-governing parties and the potential for another round of early elections—revived turbulence in Italian markets last week. We have warned in the past that an Italian exit from the euro would be disastrous not only for Italy, but for many others as well (see our earlier post).

And, given Italy’s high public debt, a significant easing of its fiscal stance within monetary union could revive financial instability, rather than boost economic growth. Depositors fearing the introduction of a parallel currency (to finance the fiscal stimulus) would have incentive to shift out of Italian banks into “safer” jurisdictions. Argentina’s experience in 2001, when the introduction of quasi-moneys by the fiscal authorities undermined monetary control, is instructive….

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Time Consistency: A Primer

The problem of time consistency is one of the most profound in social science. With applications in areas ranging from economic policy to counterterrorism, it arises whenever the effectiveness of a policy today depends on the credibility of the commitment to implement that policy in the future.

For simplicity, we will define a time consistent policy as one where a future policymaker lacks the opportunity or the incentive to renege. Conversely, a policy lacks time consistency when a future policymaker has both the means and the motivation to break the commitment.

In this post, we describe the conceptual origins of time consistency. To emphasize its broad importance, we provide three economic examples—in monetary policy, prudential regulation, and tax policy—where the impact of the idea is especially notable....

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