This paper shows that the inability to use monetary policy for macroeconomic stabilization leaves a government more vulnerable to a rollover crisis. We study a sovereign default model with self-fulfilling rollover crises, foreign currency debt, and nominal rigidities. When the government lacks monetary autonomy, lenders anticipate that the government will face a severe recession in the event of a liquidity crisis, and are therefore more prone to run on government bonds. By contrast, a government with monetary autonomy can stabilize the economy and can easily remain immune to a rollover crisis. In a quantitative application, we find that the lack of monetary autonomy played a central role in making the Eurozone vulnerable to a rollover crisis. A lender of last resort can help ease the costs from giving up monetary independence.

Time-varying risk is the primary force driving nominal interest rate differentials on currency-denominated bonds. This finding is an immediate implication of the fact that exchange rates are roughly random walks. We show that a general equilibrium monetary model with an endogenous source of risk variation—a variable degree of asset market segmentation—can produce key features of actual interest rates and exchange rates. The endogenous segmentation arises from a fixed cost for agents to exchange money for assets. As inflation varies, the benefit of asset market participation varies, and that changes the fraction of agents participating. These effects lead the risk premium to vary systematically with the level of inflation. Our model produces variation in the risk premium even though the fundamental shocks have constant conditional variances.

We study financial panics in a small open economy with floating exchange rates. In our model, bank runs trigger a decline in domestic wealth and a currency depreciation. Runs are more likely when banks have dollar debt. Dollar debt emerges endogenously in response to the precautionary motive of domestic savers: dollar savings provide insurance against crises; so when crises are possible it becomes relatively more expensive for banks to borrow in local currency, which gives them an incentive to issue dollar debt. This feedback between aggregate risk and savers’ behavior can generate multiple equilibria, with the bad equilibrium characterized by financial dollarization and the possibility of bank runs. A domestic lender of last resort can eliminate the bad equilibrium, but interventions need to be fiscally credible. Holding foreign currency reserves hedges the fiscal position of the government and enhances its credibility, thus improving financial stability.

Before the advent of sophisticated international financial markets, a widely accepted belief was that within a monetary union, a union-wide authority orchestrating fiscal transfers between countries is necessary to provide adequate insurance against country-specific economic fluctuations. A natural question is then: Do sophisticated international financial markets obviate the need for such an active union-wide authority? We argue that they do. Specifically, we show that in a benchmark economy with no international financial markets, an activist union-wide authority is necessary to achieve desirable outcomes. With sophisticated financial markets, however, such an authority is unnecessary if its only goal is to provide cross-country insurance. Since restricting the set of policy instruments available to member countries does not create a fiscal externality across them, this result holds in a wide variety of settings. Finally, we establish that an activist union-wide authority concerned just with providing insurance across member countries is optimal only when individual countries are either unable or unwilling to pursue desirable policies

Under mild assumptions, the data indicate that fluctuations in nominal interest rate differentials across currencies are primarily fluctuations in time-varying risk. This finding is an immediate implication of the fact that exchange rates are roughly random walks. If most fluctuations in interest differentials are thought to be driven by monetary policy, then the data call for a theory which explains how changes in monetary policy change risk. Here we propose such a theory based on a general equilibrium monetary model with an endogenous source of risk variation—a variable degree of asset market segmentation.

Financial crises are widely argued to be due to herd behavior. Yet recently developed models of herd behavior have been subjected to two critiques which seem to make them inapplicable to financial crises. Herds disappear from these models if two of their unappealing assumptions are modified: if their zero-one investment decisions are made continuous and if their investors are allowed to trade assets with market-determined prices. However, both critiques are overturned—herds reappear in these models—once another of their unappealing assumptions is modified: if, instead of moving in a prespecified order, investors can move whenever they choose.

This paper measures the output costs of sovereign risk by combining a sovereign debt model with firm- and bank-level data. In our framework, an increase in sovereign risk lowers the price of government debt and has an adverse impact on banks’ balance sheets, disrupting their ability to finance firms. Importantly, firms are not equally affected by these developments: those that have greater financing needs and borrow from banks that are more exposed to government debt cut their production the most in a debt crisis. We measure the extent of this heterogeneity using Italian data and parameterize the model to match these cross-sectional facts. In counterfactual analysis, we find that heightened sovereign risk was responsible for one-third of the observed output decline during the 2011-2012 crisis in Italy.