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.

Solving non-linear stochastic models by parameterizing expectations: An application to asset pricing with production

A new algorithm called the parameterized expectations approach(PEA) for solving dynamic stochastic models under rational expectationsis developed and its advantages and disadvantages are discussed. Thisalgorithm can, in principle, approximate the true equilibrium arbitrarilywell. Also, this algorithm works from the Euler equations, so that theequilibrium does not have to be cast in the form of a planner's problem.Monte--Carlo integration and the absence of grids on the state variables,cause the computation costs not to go up exponentially when the numberof state variables or the exogenous shocks in the economy increase. \\As an application we analyze an asset pricing model with endogenousproduction. We analyze its implications for time dependence of volatilityof stock returns and the term structure of interest rates. We argue thatthis model can generate hump--shaped term structures.

A unifying approach to the empirical evaluation of asset pricing models

Two main approaches are commonly used to empirically evaluate linear factor pricingmodels: regression and SDF methods, with centred and uncentred versions of the latter.We show that unlike standard two-step or iterated GMM procedures, single-step estimatorssuch as continuously updated GMM yield numerically identical values for prices of risk,pricing errors, Jensen s alphas and overidentifying restrictions tests irrespective of the modelvalidity. Therefore, there is arguably a single approach regardless of the factors being tradedor not, or the use of excess or gross returns. We illustrate our results by revisiting Lustigand Verdelhan s (2007) empirical analysis of currency returns.

Keeping up with the Joneses: An international asset pricing model

We derive an international asset pricing model that assumes local investorshave preferences of the type "keeping up with the Joneses." In aninternational setting investors compare their current wealth with that oftheir peers who live in the same country. In the process of inferring thecountry's average wealth, investors incorporate information from the domesticmarket portfolio. In equilibrium, this gives rise to a multifactor CAPMwhere, together with the world market price of risk, there existscountry-speciffic prices of risk associated with deviations from thecountry's average wealth level. The model performs signifficantly better, interms of explaining cross-section of returns, than the international CAPM.Moreover, the results are robust, both for conditional and unconditionaltests, to the inclusion of currency risk, macroeconomic sources of risk andthe Fama and French HML factor.

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.

Asset pricing implications of benchmarking: A two-factor CAPM

In this paper we consider the equilibrium effects of an institutionalinvestor whose performance is benchmarked to an index. In a partialequilibrium setting, the objective of the institutional investor is modeledas the maximization of expected utility (an increasing and concave function,in order to accommodate risk aversion) of final wealth minus a benchmark.In equilibrium this optimal strategy gives rise to the two-beta CAPM inBrennan (1993): together with the market beta a new risk-factor (that wecall active management risk) is brought into the analysis. This new betais deffined as the normalized (to the benchmark's variance) covariancebetween the asset excess return and the excess return of the market overthe benchmark index. Different to Brennan, the empirical test supports themodel's predictions. The cross-section return on the active management riskis positive and signifficant especially after 1990, when institutionalinvestors have become the representative agent of the market.

Asset pricing with idiosyncratic risk and overlapping generations

A number of existing studies have concluded that risk sharing allocations supported by competitive, incomplete markets equilibria are quantitatively close to first-best. Equilibrium asset prices in these models have been difficult to distinguish from those associated with a complete markets model, the counterfactual features of which have been widely documented. This paper asks if life cycle considerations, in conjunction with persistent idiosyncratic shocks which become more volatile during aggregate downturns, can reconcile the quantitative properties of the competitive asset pricing framework with those of observed asset returns. We begin by arguing that data from the Panel Study on Income Dynamics support the plausibility of such a shock process. Our estimates suggest a high degree of persistence as well as a substantial increase in idiosyncratic conditional volatility coincident with periods of low growth in U.S. GNP. When these factors are incorporated in a stationary overlapping generations framework, the implications for the returns on risky assets are substantial. Plausible parameterizations of our economy are able to generate Sharpe ratios which match those observed in U.S. data. Our economy cannot, however, account for the level of variability of stock returns, owing in large part to the specification of its production technology.

Asset prices and the measurement of wealth and saving

The paper defines concepts of real wealth and saving which take into account the intertemporal index number problem that results from changing interest rates. Unlike conventional measures of real wealth, which are based on the market value of assets and ignore the index number problem, the new measure correctly reflects the changes in the welfare of households over time. An empirically operational approximation to the theoretical measure is provided and applied to US data. A major empirical finding is that US real financial wealth increased strongly in the 1980s, much more than is revealed by the market value of assets.

Job search and asset accumulation under borrowing constraints

In this paper I show how borrowing constraints and job search interact.I fit a dynamic model to data from the National Longitudinal Survey(1979-cohort) and show that borrowing constraints are significant. Agentswith more initial assets and more access to credit attain higher wagesfor several periods after high school graduation. The unemployed maintaintheir consumption by running down their assets, while the employed saveto buffer against future unemployment spells. I also show that, unlikein models with exogenous income streams, unemployment transfers, byallowing agents to attain higher wages do not 'crowd out' but increasesaving.

KemapMobile: una adaptación de la herramienta software KeMap a la plataforma Android

Este trabajo describe el proceso de creación de la herramienta de software KemapMobile para la plataforma Android. El artefacto es una adaptación del software de escritorio KeMap que se integra en la plataforma educativa VerilUOC y permite a los estudiantes conectarse a ella para descargar, en la aplicación, ejercicios con los que poner a prueba y afianzar sus conocimientos sobre la simplificación de funciones lógicas booleanas con mapas de Karnaugh y tablas de verdad. La arquitectura cliente-servidor de la aplicación permite a los estudiantes disponer de ejercicios personalizados y al profesorado obtener datos sobre el uso de la herramienta y sobre la progresión del alumnado.

Laboratorio virtual de química en software libre para la preparación de disoluciones

Con este TFM se muestra un laboratorio virtual de química a través de diversos experimentos para la preparación de disoluciones en función de sus expresiones de concentración.

Monetary policy and rational asset price bubbles

I examine the impact of alternative monetary policy rules on arational asset price bubble, through the lens of an overlapping generations model with nominal rigidities. A systematic increase in interestrates in response to a growing bubble is shown to enhance the fluctuations in the latter, through its positive effect on bubble growth. Theoptimal monetary policy seeks to strike a balance between stabilization of the bubble and stabilization of aggregate demand. The paper'smain findings call into question the theoretical foundations of the casefor "leaning against the wind" monetary policies.

Software lliure aplicat a un institut

Aquest projecte intenta donar una alternativa al software privatiu, fent servir el software lliure, i per aconseguir aquest objectiu es crea una distribució GNU/Linux adaptada a les necessitats del institut IES Sabadell. També es realitza un petit estudi dels dos tipus de software, lliure i privatiu, en que es mostrà la historia, tipus de llicències, models de negoci i les avantatges que tenen.