Theoretical notes on bubbles and the current crisis

We explore a view of the crisis as a shock to investor sentiment that led to the collapse of abubble or pyramid scheme in financial markets. We embed this view in a standard model of thefinancial accelerator and explore its empirical and policy implications. In particular, we show howthe model can account for: (i) a gradual and protracted expansionary phase followed by a suddenand sharp recession; (ii) the connection (or lack of connection!) between financial and real economicactivity and; (iii) a fast and strong transmission of shocks across countries. We also use the modelto explore the role of fiscal policy.

On the impact of leverage constraints on asset prices and trading volume

Researchers have used stylized facts on asset prices and trading volumein stock markets (in particular, the mean reversion of asset returnsand the correlations between trading volume, price changes and pricelevels) to support theories where agents are not rational expected utilitymaximizers. This paper shows that this empirical evidence is in factconsistent with a standard infite horizon perfect information expectedutility economy where some agents face leverage constraints similar tothose found in todays financial markets. In addition, and in sharpcontrast to the theories above, we explain some qualitative differencesthat are observed in the price-volume relation on stock and on futuresmarkets. We consider a continuous-time economy where agents maximize theintegral of their discounted utility from consumption under both budgetand leverage con-straints. Building on the work by Vila and Zariphopoulou(1997), we find a closed form solution, up to a negative constant, for theequilibrium prices and demands in the region of the state space where theconstraint is non-binding. We show that, at the equilibrium, stock holdingsvolatility as well as its ratio to stock price volatility are increasingfunctions of the stock price and interpret this finding in terms of theprice-volume relation.

On the cultural transmission of corruption

We provide a cultural explanation to the phenomenon of corruption in the framework of an overlapping generations model with intergenerational transmissionof values. We show that the economy has two steady states with different levels of corruption. The driving force in the equilibrium selection process is the education effort exerted by parents which depends on the distribution of ethics in the population and on expectations about future policies. We propose some policy interventions which via parents' efforts have long-lasting effects on corruption and show the success of intensive education campaigns. Educating the young is a key element in reducing corruption successfully.

Credit constraints in general equilibrium: Experimental results

Our work attempts to investigate the influence of credit tightness orexpansion on activity and relative prices in a multimarket set-up. We report on somedouble- auction, two-market experiments where subjects had to satisfy an inequalityinvolving the use of credit. The experiments display two regimes, characterizedby high and low credit availability. The critical value of credit at the commonboundary of the two regimes has a compelling interpretation as the maximal credituse at the Arrow-Debreu equilibrium of the abstract economy naturally associatedto our experimental environment. Our main results are that changes in theavailability of credit: (a): have minor and unsystematic effects on quantitiesand relative prices in the high-credit regime, (b): have substantial effects, bothon quantities and relative prices, in the low-credit regime.

Portfolio delegation under short-selling constraints

In this paper we study delegated portfolio management when themanager's ability to short-sell is restricted. Contrary to previousresults, we show that under moral hazard, linear performance-adjustedcontracts do provide portfolio managers with incentives to gatherinformation. The risk-averse manager's optimal effort is an increasingfunction of her share in the portfolio's return. This result affectsthe risk-averse investor's optimal contract decision. The first best,purely risk-sharing contract is proved to be suboptimal. Usingnumerical methods we show that the manager's share in the portfolioreturn is higher than the rst best share. Additionally, this deviationis shown to be: (i) increasing in the manager's risk aversion and (ii)larger for tighter short-selling restrictions. When the constraint isrelaxed the optimal contract converges towards the first best risksharing contract.

Institutional constraints on organizations: The case of Spanish car dealerships

We study the effect of organizational choice and institutions on the performance ofSpanish car dealerships. Using outlet-level data from 1994, we find that verticallyintegrateddealerships showed substantially lower labor productivity, higher labor costs andlower profitability than franchised ones. Despite these gaps in performance, no verticallyintegratedoutlet was separated until 1994, yet the few outlets that were eventuallyseparated systematically improved their performance. We argue that the conversion ofintegrated outlets into franchised ones involved significant transaction costs, due to aninstitutional environment favoring permanent, highly-unionized employment relations. Inline with this argument, we find that the observed separations occurred in distributionnetworks that underwent marked reductions in worker unionization rates, following thelegalization of temporary labor contracts.

Financing constraints, irreversibility and investment dynamics

We develop a model of an industry with many heterogeneous firms that face both financingconstraints and irreversibility constraints. The financing constraint implies that firmscannot borrow unless the debt is secured by collateral; the irreversibility constraint thatthey can only sell their fixed capital by selling their business. We use this model to examinethe cyclical behavior of aggregate fixed investment, variable capital investment, and outputin the presence of persistent idiosyncratic and aggregate shocks. Our model yields threemain results. First, the effect of the irreversibility constraint on fixed capital investmentis reinforced by the financing constraint. Second, the effect of the financing constraint onvariable capital investment is reinforced by the irreversibility constraint. Finally, the interactionbetween the two constraints is key for explaining why input inventories and materialdeliveries of US manufacturing firms are so volatile and procyclical, and also why they arehighly asymmetrical over the business cycle.

Testing financing constraints on firm investment using variable capital

We consider a dynamic multifactor model of investment with financing imperfections,adjustment costs and fixed and variable capital. We use the model to derive a test offinancing constraints based on a reduced form variable capital equation. Simulation resultsshow that this test correctly identifies financially constrained firms even when the estimationof firms investment opportunities is very noisy. In addition, the test is well specified inthe presence of both concave and convex adjustment costs of fixed capital. We confirmempirically the validity of this test on a sample of small Italian manufacturing companies.

Sources and propagation of international cycles: Common shocks or transmission?

This paper studies the generation and transmission of international cycles in a multi-country model with production and consumption interdependencies. Two sources of disturbance are considered and three channels of propagation are compared. In the short run the contemporaneous correlation of disturbances determines the main features of the transmission. In the medium run production interdependencies account for the transmission of technology shocks and consumption interdependencies account for the transmission of government shocks. Technology disturbances, which are mildly correlated across countries, are more successful than government expenditure disturbances in reproducing actual data. The model also accounts for the low cross country consumption correlations observed in the data.

Monetary policy shocks and transmission in Italy: A VAR analysis

This paper provides updated empirical evidence about the real and nominal effects of monetary policy in Italy, by using structural VAR analysis. We discuss different empirical approaches that have been used in order to identify monetary policy exogenous shocks. We argue that the data support the view that the Bank of Italy, at least in the recent past, has been targeting the rate on overnight interbank loans. Therefore, we interpret shocks to the overnight rate as purely exogenous monetary policy shocks and study how different macroeconomic variables react to such shocks.

The transmission of US shocks to Latin America

I study whether and how US shocks are transmitted to eight Latin American countries. US shocks are identified using sign restrictions and treated as exogenous with respect to Latin American economies. Posterior estimates for individual and average effects are constructed. US monetary shocks produce significant fluctuations in Latin America, but real demand and supply shocks do not. Floaters and currency boarders display similar output but different inflation and interest rate responses. The financial channel plays a crucial role in the transmission. US disturbances explain important portions of the variability of LatinAmerican macrovariables, producing continental cyclical fluctuations and, in two episodes, destabilizing nominal exchange rate effects. Policy implications are discussed.

Credit constraints, firms' precautionary investment and the business cycle

This paper studies the macroeconomic implications of firms' investment composition choices in the presence of credit constraints. Following a negative andpersistent aggregate productivity shock, firms shift into short-term investments because they produce more pledgeable output and because they help alleviate futureborrowing constraints. This produces a short-run dampening of the effects of theshock, at the expense of lower long-term investment and future output, relativeto an economy with no credit market imperfections. The effects are exacerbatedby a steepening of the term structure of interest rates that further encourages ashift towards short-term investments in the short-run. Small temporary shocks tothe severity of financing frictions generate large and long-lasting effects on outputthrough their impact on the composition of investment. A positive financial shockproduces much stronger effects than an identical negative shock, while the responsesto positive and negative shocks to aggregate productivity are roughly symmetric.Finally, the paper introduces a novel explanation for the countercyclicality of financing constraints of firms.

Job creation under liquidity constraints: The Spanish case

This paper shows that liquidity constraints restrict jobcreation even when labor markets are flexible. In a dynamicmodel of labor demand, I show that in an environment of imperfect capital and imperfect labor markets, firms usetemporary contracts to relax financial constraints. Evidence for the predictions of the model is presented using Spanish data from the CBBE (Central de Balances del Banco de España - Balance Sheet data from the Bank of Spain). It is shown that firms substitute temporary laborfor permanent one and use less debt as their financial position improves. In particular, it is rejected that Spanish firms operate in an environment of free capital markets and of no labor adjustment costs. The labor reform of 1984, which created temporary contracts, implied to some extent a relaxation of liquidity constraints.Accordingly, firms used these contracts more extensivelyand used less debt; however, as capital markets continueto be imperfect, permanent job creation continues to beslow. Consequently, relaxation of liquidity constraints should also be part of a job creation strategy.

Optimal information transmission in organizations: Search and congestion

We propose a stylized model of a problem-solving organization whoseinternal communication structure is given by a fixed network. Problemsarrive randomly anywhere in this network and must find their way to theirrespective specialized solvers by relying on local information alone.The organization handles multiple problems simultaneously. For this reason,the process may be subject to congestion. We provide a characterization ofthe threshold of collapse of the network and of the stock of foatingproblems (or average delay) that prevails below that threshold. We buildupon this characterization to address a design problem: the determinationof what kind of network architecture optimizes performance for any givenproblem arrival rate. We conclude that, for low arrival rates, the optimalnetwork is very polarized (i.e. star-like or centralized ), whereas it islargely homogenous (or decentralized ) for high arrival rates. We also showthat, if an auxiliary assumption holds, the transition between these twoopposite structures is sharp and they are the only ones to ever qualify asoptimal.