A Bayesian approach to model changes in volatility in the Mexican stock exchange index

We model the changes in volatility in the Mexican Stock Exchange Index using a Bayesian approach. We study the time series with a wide set of models characterized by a Markov switching heterogeneity. The advantage of this approach is that it allows for a broader spectrum of possible models since the estimation of the moments of the parameters is done using the finite mixture distribution MCMC method, without relying on assumptions about large sampling and mathematical optimization. This is particularly relevant for emerging markets’ financial data because of its special characteristics, like being more susceptible to jumps and changes in volatility caused by exchange rate swings, financial crises and oil and commodity prices. For model comparison, we use the marginal likelihood approach and the bridge sampling technique. The best representation of the data is given by a switching model with three states rather than any other autoregressive linear or non-linear model. The periods of volatility found by the model coincide with different financial crisis. Whereas other studies of volatility for the same market impose the Markovian model that captures changes in volatility, we let our model to be defined in an endogenous way.     

Determinants of Technical Efficiency in Small Firms

There is evidence that small firms are less productive than larger ones. This phenomenon could be explained by several factors. In this paper, using plant survey data and non-parametric deterministic frontier methodology, we explore what factors can explain the observed differences in technical efficiency. In the case of Chilean manufacturing firms, we found that efficiency is positively associated with the experience of workers, modernization of physical capital and innovation in products. In contrast, other variables such as outward orientation, owner education and participation in some public programs do not affect the efficiency of the firms.     

The Place of Uncertainty in Heterodox Economics Journals: A Bibliometric Study

Uncertainty is a common theme in heterodox economics. This article investigates how heterodox journals have been dealing with the concept of uncertainty. It relies on a bibliometric analysis to identify the concept of uncertainty in top heterodox journals and the genealogy of different heterodox meanings of uncertainty among those journals.     

Analysis of the emergency service applying the queueing theory

Those responsible for the decision-making in hospitals are becoming more aware of the need to efficiently manage hospital systems. One option is the queueing models. In this work, the Emergency service of a public hospital is analyzed by applying the concepts and relations of queues. Based on the results of the model, it is concluded that the Emergency area does not count with the minimum number of doctors necessary for a constant flow of patients. The minimum number of doctors necessary to satisfy the current and future service demand, with the same service times and service disciplines, is calculated using the model. The analytical models allow to directly understand the existing relations between service demand, number of doctors and the attention priority of the patient seen as a system of queues. The work is of use to managers and those responsible for the management of hospital systems.     

Estimation and forecasting in vector autoregressive moving average models for rich datasets

We address the issue of modelling and forecasting macroeconomic variables using rich datasets by adopting the class of Vector Autoregressive Moving Average (VARMA) models. We overcome the estimation issue that arises with this class of models by implementing an iterative ordinary least squares (IOLS) estimator. We establish the consistency and asymptotic distribution of the estimator for weak and strong VARMA(p,q) models. Monte Carlo results show that IOLS is consistent and feasible for large systems, outperforming the MLE and other linear regression based efficient estimators under alternative scenarios. Our empirical application shows that VARMA models are feasible alternatives when forecasting with many predictors. We show that VARMA models outperform the AR(1), ARMA(1,1), Bayesian VAR, and factor models, considering different model dimensions.     

Bootstrap validity for the score test when instruments may be weak

It is well-known that size adjustments based on bootstrapping the t$t$-statistic perform poorly when instruments are weakly correlated with the endogenous explanatory variable. In this paper, we provide a theoretical proof that guarantees the validity of the bootstrap for the score statistic. This theory does not follow from standard results, since the score statistic is not a smooth function of sample means and some parameters are not consistently estimable when the instruments are uncorrelated with the explanatory variable.     

Responsibility or autonomy: children and the probability of self-employment in the USA

This paper studies the effect of children on the likelihood of self-employment. Having children can change preferences that are central to the decision whether to be self-employed. On the one hand, individuals’ preference for autonomy and flexibility increases when having children, which increases the willingness to be self-employed. On the other hand, having children entails a responsibility over someone else, which increases individual risk aversion and decreases the willingness to be self-employed. Using a pooled cross section of 26 years from the General Social Survey, instrumental variable estimates indicate that, in the USA, having children under the age of 18 in the household decreases the likelihood of being self-employed by 11 % (i.e., the responsibility effect dominates). This effect is considerable as a child decreases the probability of self-employment more than the increase associated with being raised by a self-employed father—one of the main determinants of self-employment.     

Do central bank foreign exchange interventions affect market expectations?

The aim of this article is to study the impact of the Brazilian central bank swap interventions on the FX market from 2006 to 2013. In this period, these nontraditional interventions were the main FX instrument of the Brazilian Government. Since the central bank operates through a sequence of daily interventions in most of the period, we employ the event study method, which is appropriate to investigate cumulative impact of intervention episodes. We analyse the effects on the risk neutral distribution of BRL-USD exchange rate, which incorporates economic valuation besides the likelihoods. We investigate both changes in level and in the dynamics of the moments. Our tests indicate that interventions have little effects on the exchange rate distribution. We only find evidences of some impact on the dynamics of the mean, volatility and skewness over long horizons when the central bank takes short positions on the exchange rate.     

Securitization without risk transfer

We analyze asset-backed commercial paper conduits, which experienced a shadow-banking run and played a central role in the early phase of the financial crisis of 2007–2009. We document that commercial banks set up conduits to securitize assets worth $1.3 trillion while insuring the newly securitized assets using explicit guarantees. We show that regulatory arbitrage was an important motive behind setting up conduits. In particular, the guarantees were structured so as to reduce regulatory capital requirements, more so by banks with less capital, and while still providing recourse to bank balance sheets for outside investors. Consistent with such recourse, we find that conduits provided little risk transfer during the run, as losses from conduits remained with banks instead of outside investors and banks with more exposure to conduits had lower stock returns.     

Auctions of licences and market structure

Summary. This paper studies sequential auctions of licences to participate in a symmetric market game. Assuming that the rate at which industry profits decrease with repeated entry is not too large, at the unique solution either a single firm preempts entry altogether or entry occurs in every stage, depending on the net benefit of complete preemption to an incumbent. If we relax the assumption, a third outcome can occur: two firms may coordinate their choices to avoid further entry. The analysis employs a new refinement of Nash equilibrium, the concept of recursively undominated equilibrium. Received: February 25, 2000; revised version: September 12, 2000