Fiscal Policy and Financial Depth

Most economists and observers place the lack of fiscal discipline at the core of the recent Argentine crisis. This begs the question of how countries like Belgium or Italy (pre-Maastricht) could run large fiscal deficits and accumulate debts far beyond those of Argentina, without experiencing crises nearly as dramatic as that of Argentina? Why is it that Argentina cannot act like Belgium or Italy and pursue expansionary fiscal policy during downturns? We argue that advanced and emerging economies differ in their financial depth, and show that lack of financial depth constrains fiscal policy in a way that can overturn standard Keynesian fiscal policy prescriptions. We also provide empirical support for this viewpoint. Crowding out is systematically larger in emerging markets than in developed economies. More importantly, this difference is extreme during crises, when the crowding out coefficient exceeds one in emerging market economies.

A Dual Liquidity Model for Emerging Markets

The last few years have seen a significant re-evaluation of the models used to analyze crises in emerging markets. Recent models typically stress financial constraints or distorted financial incentives. While this certainly represents progress, these models share a weakness with the earlier work: neither is uniquely about emerging markets. Adaptations of the Mundell-Fleming model represent Argentina as a Belgium with larger external shocks. Likewise, emerging market models of financial constraints are adaptations of developed economy ones with tighter financial constraints. In our work, we have advocated a model which distinguishes between the financial constraints affecting borrowing and lending among agents within an emerging economy, and those affecting borrowing from foreign lenders. This 'dual liquidity' model offers a parsimonious description of the behavior of firms, governments, and asset prices during financial crises. It also provides prescriptions for optimal policy responses to these crises.

International Liquidity Management: Sterilization Policy in Illiquid Financial Markets

During the booms that precede crises in emerging economies, policy makers often struggle to limit capital flows and their expansionary consequences. The main policy tool for this task is sterilization - essentially a swap of international reserves for public bonds. However, there is an extensive debate on the effectiveness of this policy, with many arguing that it may be counterproductive once the (over-) reaction of the private sector is considered. But what forces account for the private sector's reaction remain largely unexplained. In this paper we provide a model to discuss these issues. We emphasize the international liquidity management aspect of sterilization over the traditional monetary one, a re-focus that seems warranted when the main concern is external crisis prevention. We first demonstrate that policies to smooth expansion in anticipation of downturns can be Pareto improving in economies where domestic financial markets are underdeveloped. We then discuss the implementation and effectiveness of this policy via sterilization. The greatest risk of policy arises in situations where policy is most needed - that is , when financial markets are illiquid. Our mechanism is akin to the implicit bailout' problem, although the central bank acts non-selectively and only intervenes through open markets in our model. Illiquidity replaces corruption and ineptitude. In addition to an appreciation of the currency and the emergence of a quasi-fiscal deficit, the private sector's reaction to sterilization may lead to an expansion rather than the desired contraction in aggregate demand or nontradeables investment and to a bias toward short term capital inflows. The main insights extend to international liquidity management issues more generally.

Musical chairs: a comment on the credit crisis.

Uncertainty –that is, a rise in unknown and immeasurable risk rather than the measurable risk that the financial sector specializes in managing– is at the heart of the recent liquidity crisis. The financial instruments and derivative structures underpinning the recent growth in credit markets are complex. Because of the rapid proliferation of these instruments, market participants cannot refer to a historical record to measure how these financial structures will behave during a time of stress. These two factors, complexity and lack of history, are the preconditions for rampant uncertainty. We explain how a rise in uncertainty can cause a liquidity crisis and discuss central bank policies in this context.

Inflation Targeting and Sudden Stops

Emerging economies experience sudden stops in capital inflows. As we have argued in Caballero and Krishnamurthy (2002), having access to monetary policy during these sudden stops is useful, but mostly for insurance' rather than for aggregate demand reasons. In this environment, a central bank that cannot commit to monetary policy choices will ignore the insurance aspect and follow a procyclical rather than the optimal countercyclical monetary policy. The central bank will also intervene excessively to support the exchange rate. These inefficiencies are exacerbated by the presence of an expansionary bias. In order to solve these problems, we propose modifying the central bank's objective to (i) include state-contingent inflation targets, (ii) target a measure of inflation that overweights non-tradable inflation

Collective Risk Management in a Flight to Quality Episode

We present a model of optimal intervention in a flight to quality episode. The reason for intervention stems from a collective bias in agents' expectations. Agents in the model make risk management decisions with incomplete knowledge. They understand their own shocks, but are uncertain of how correlated their shocks are with systemwide shocks, treating the latter uncertainty as Knightian. We show that when aggregate liquidity is low, an increase in uncertainty leads agents to a series of protective actions -- decreasing risk exposures, hoarding liquidity, locking-up capital -- that reflect a flight to quality. However, the conservative actions of agents leave the aggregate economy over-exposed to negative shocks. Each agent covers himself against his own worst-case scenario, but the scenario that the collective of agents are guarding against is impossible. A lender of last resort, even if less knowledgeable than private agents about individual shocks, does not suffer from this collective bias and finds that pledging intervention in extreme events is valuable. The intervention unlocks private capital markets.

Strong-coupling expansion for ultracold bosons in an optical lattice at finite temperatures in the presence of superfluidity

We develop a strong-coupling ($t \ll U$) expansion technique for calculating the density profile for bosonic atoms trapped in an optical lattice with an overall harmonic trap at finite temperature and finite on site interaction in the presence of superfluid regions. Our results match well with quantum Monte Carlo simulations at finite temperature. We also show that the superfluid order parameter never vanishes in the trap due to proximity effect. Our calculations for the scaled density in the vacuum to superfluid transition agree well with the experimental data for appropriate temperatures. We present calculations for the entropy per particle as a function of temperature which can be used to calibrate the temperature in experiments. We also discuss issues connected with the demonstration of universal quantum critical scaling in the experiments.Comment: 11 pages, 9 figure

Quasi-universal transient behavior of a nonequilibrium Mott insulator driven by an electric field

We use a self-consistent strong-coupling expansion for the self-energy (perturbation theory in the hopping) to describe the nonequilibrium dynamics of strongly correlated lattice fermions. We study the three-dimensional homogeneous Fermi-Hubbard model driven by an external electric field showing that the damping of the ensuing Bloch oscillations depends on the direction of the field, and that for a broad range of field strengths, a long-lived transient prethermalized state emerges. This long-lived transient regime implies that thermal equilibrium may be out of reach of the time scales accessible in present cold atom experiments, but shows that an interesting new quasi-universal transient state exists in nonequilibrium governed by a thermalized kinetic energy but not a thermalized potential energy. In addition, when the field strength is equal in magnitude to the interaction between atoms, the system undergoes a rapid thermalization, characterized by a different quasi-universal behavior of the current and spectral function for different values of the hopping.Comment: (5 pages, 5 figures, ReVTeX