The Impact of Oportunidades on Consumption,Savings and Transfers*

In this paper, we estimate the effect of the Mexican conditional cash transfer programme, Oportunidades, on transfers, savings and consumption for treated households. We find positive effects on consumption of non‐durable and durable goods, an increase in savings coupled with a drop in the number and values of loans, and a reduction of in‐kind transfers received by households in treatment areas. These results are consistent with the existing evidence that conditional cash transfer programmes have beneficial effects in both the short and medium term, but that they partly crowd out private transfers.     

Task assignment,incentives and technological factors

In this paper, we examine the allocation of tasks between a principal and an agent considering their incentives to provide effort, their different abilities in handling tasks, and transmission costs. We focus our attention on two tasks: the first may be handled by the principal or by the agent, whereas the second is necessarily carried out by the agent. Under a fully decentralised organisation, the agent performs both tasks, whereas, under partial delegation, the principal handles the first task and transfers the outcome to the agent who handles the second task. Assuming technological complementarities, from our analysis it emerges that, if there is imperfect observability of effort, full delegation is better at eliciting effort by the agent in the second task, whereas, in comparison with partial delegation, it lowers effort in the first task. Although with contractible effort, the choice between the two organisational forms depends only on transmission costs and on the relative ability of its members, when moral hazard problems are taken into account, the organisational choice is related to the relative importance played by the two tasks in production. If the agent's task is relatively important in production, full delegation, encouraging a higher level of effort in this task, may be optimal, even if technological factors favour partial delegation. Copyright © 2008 John Wiley & Sons, Ltd.     

Extending a Logistic Approach to Risk Modeling through Semiparametric Mixing

The new proposal of the Basel Committee on banking regulation issued in January 2001 allows banks to use internal ratings systems to classify firms. Within this context, the main problem is to find a model that fits the data as well as possible, but one that also provides good prediction and explicative capabilities. In this paper, our aim is to compare two kinds of classification models applied to creditworthiness using weighted classification error as the performance function: the standard logistic model and a mixed logistic model, adopting, respectively, a parametric and a semiparametric approach. The main problem of the former is related to the assumption of an i.i.d. hypothesis, but it is often necessary to consider the possible presence of unobservable heterogeneity that characterizes microeconomic data. To better consider this phenomenon, we defined and applied a random effect logistic model, avoiding parametric assumptions upon the random effect distribution. This leads to a likelihood that is defined as the integral of the kernel density with respect to the mixing density, which has no analytical solution. This problem can be obviated by approximating the integral with a finite sum of kernel densities, each one characterized by a different set of model parameters. This discrete nature helps us in detecting non-overlapping clusters characterized by homogeneous values of insolvency risk, and in classifying firms to one of these clusters by means of estimated posterior probabilities of component membership.     

Investment and liquidation in renegotiation-proof contracts with moral hazard

In a long-term contract with moral hazard, the liquidation of the firm can arise as the outcome of the optimal contract. However, if the future production capability or market opportunities remain unchanged, liquidation may not be free from renegotiation. Will the firm ever be liquidated if we allow for renegotiation? This paper shows that the firm can still be liquidated even though liquidation is not free from renegotiation in the long-term contract. In addition to liquidation, the renegotiation-proof contract generates important features of the investment behavior and dynamics of firms observed in the data.     

A generalization of the Hull and White formula with applications to option pricing approximation

By means of Malliavin calculus we see that the classical Hull and White formula for option pricing can be extended to the case where the volatility and the noise driving the stock prices are correlated. This extension will allow us to describe the effect of correlation on option prices and to derive approximate option pricing formulas.A previous version of this paper has benefited from helpful comments by two anonymous referees.     

A numerical method to price exotic path-dependent options on an underlying described by the Heston stochastic volatility model

We consider the problem of pricing European exotic path-dependent derivatives on an underlying described by the Heston stochastic volatility model. Lipton has found a closed form integral representation of the joint transition probability density function of underlying price and variance in the Heston model. We give a convenient numerical approximation of this formula and we use the obtained approximated transition probability density function to price discrete path-dependent options as discounted expectations. The expected value of the payoff is calculated evaluating an integral with the Monte Carlo method using a variance reduction technique based on a suitable approximation of the transition probability density function of the Heston model. As a test case, we evaluate the price of a discrete arithmetic average Asian option, when the average over n = 12 prices is considered, that is when the integral to evaluate is a 2n = 24 dimensional integral. We show that the method proposed is computationally efficient and gives accurate results.     

Asymptotical behavior of finite and possible discontinuous economies

We consider a finite economy in which the data are depending on an exogenous parameter and the utilities satisfy a condition, previously introduced by the authors and called sequential pseudocontinuity, weaker than sequential lower semicontinuity and than sequential upper semicontinuity. We show that the economy has a nice asymptotical behavior, that is: for any sequence (x _n ) _n of exogenous parameters converging to x _o , any convergent subsequence of a sequence of approximate competitive equilibria of converges to an exact equilibrium of .      

Computing the survival probability in the Madan–Unal credit risk model: application to the CDS market

We obtain a quasi-analytical approximation of the survival probability in the credit risk model proposed in [Madan, D.B. and Unal, H., Pricing the risk of default. Rev. Deriv. Res., 1998, 2(2), 121–160]. Such a formula, which extensive numerical simulations reveal to be accurate and computationally fast, can also be employed for pricing credit default swaps (CDSs). Specifically, we derive a quasi-analytical approximate expression for CDS par spreads, and we use it to estimate the parameters of the model. The results obtained show a rather satisfactory agreement between theoretical and real market data.     

The Role of Turnover Costs in the Enforcement of Performance–Related Pay Contracts

Labour contracts which establish performance–related pay are afflicted with the firm's moral hazard problem because of the difficulty in the verifiability of performance by an external authority. Some models have explored the possibility that such contracts could be enforced through a mechanism of the firm's reputation or thanks to an excess of demand in the labour markets (unfilled job vacancies). In this paper a simple model is proposed to show the working of an alternative mechanism for performance–related pay contracts based on turnover costs, borne by firms arising from the process of hiring, training and firing. By sinking a certain amount of resources as turnover costs, employers may credibly promise to pay a bonus, if faced with the worker's threat to quit in the case of cheating, to avoid the loss of specific capital. This provides a formalization of the insight that turnover costs and specific investments might support the enforcement of implicit contracts. The welfare implications of this mechanism are worked out, showing how turnover costs on the one hand reduce the available social surplus but on the other hand increase this surplus by providing incentives for optimal effort.