Spanning with American options

In this paper, we investigate the existence of multiperiod American options generating dynamically complete markets. We show that if a primitive security separates states at the terminal date, then generically there exist multiperiod American options on that security generating dynamically complete markets. We also provide an example of an economy in which multiperiod American options on a primitive security generate dynamically complete markets, while multiperiod European options do not.     

How former business owners fare in the labor market? Job assignment and earnings

This study uses detailed longitudinal matched employer–employee data to examine the impact of entrepreneurial experience on job assignments, careers, and wages. The results suggest that there are significant differences in career mobility between former business owners and workers who were always wage employees. Former business owners enter firms at higher job levels and progress faster up the hierarchy than wage employees without entrepreneurial experience. The majority of the former business owners find jobs in small firms. The return to business ownership experience is lower than the return to wage employee experience, thus suggesting that the labor market imposes a penalty for business ownership experience.     

Mean–variance portfolio selection with ‘at-risk’ constraints and discrete distributions

We examine the impact of adding either a VaR or a CVaR constraint to the mean–variance model when security returns are assumed to have a discrete distribution with finitely many jump points. Three main results are obtained. First, portfolios on the VaR-constrained boundary exhibit (K + 2)-fund separation, where K is the number of states for which the portfolios suffer losses equal to the VaR bound. Second, portfolios on the CVaR-constrained boundary exhibit (K + 3)-fund separation, where K is the number of states for which the portfolios suffer losses equal to their VaRs. Third, an example illustrates that while the VaR of the CVaR-constrained optimal portfolio is close to that of the VaR-constrained optimal portfolio, the CVaR of the former is notably smaller than that of the latter. This result suggests that a CVaR constraint is more effective than a VaR constraint to curtail large losses in the mean–variance model.     

Serial entrepreneurship: impact of human capital on time to re-entry

This study uses a longitudinal matched employer–employee database to examine how ex-entrepreneurs’ levels of general and specific human capital influence their likelihood of re-entering entrepreneurship over time, in a different firm, thereby becoming serial entrepreneurs. The results reveal a negative effect of general human capital on the hazard of becoming a serial entrepreneur; the impact of entrepreneurial-specific human capital on the hazard of re-entering entrepreneurship is in general positive. This research provides a dynamic approach to serial entrepreneurship revealing that specific types of human capital play distinct roles on individuals’ entrepreneurial behavior.     

The Main Determinants of the Use of the Cost Accounting System in Portuguese Local Government

Abstract: This paper explores the main determinants of the use of the cost accounting system (CAS) in Portuguese local government (PLG). Regression analysis is used to study the fit of a model of accounting changes in PLG, focused on cost accounting systems oriented to activities and outputs. Based on survey data gathered from PLG, we have found that the use of information in decision‐making and external reporting is still a mirage. We obtain evidence about the influence of the internal organizational context (especially the lack of support and difficulties in the CAS implementation) in the use for internal purposes, while the institutional environment (like external pressures to implement the CAS) appears to be more deterministic of the external use. Results strengthen the function of external reporting to legitimate the organization's activities to external stakeholders. On the other hand, some control variables (like political competition, usefulness and experience) also evidence some explanatory power in the model. Some mixed results were found that appeal to further research in the future. Our empirical results contribute to understand the importance of interconnecting the contingency and institutional approaches to gain a clear picture of cost accounting changes in the public sector.     

When more is less: Using multiple constraints to reduce tail risk

Financial institutions suffered large trading losses during the 2007–2009 global financial crisis. These losses cast doubt on the effectiveness of regulations and risk management systems based on a single Value-at-Risk (VaR) constraint. While some researchers have recommended using Conditional Value-at-Risk (CVaR) to control tail risk, VaR remains popular among practitioners and regulators. Accordingly, our paper examines the effectiveness of multiple VaR constraints in controlling CVaR. Under certain conditions, we theoretically show that they are more effective than a single VaR constraint. Furthermore, we numerically find that the maximum CVaR permitted by the constraints is notably smaller than with a single constraint. These results suggest that regulations and risk management systems based on multiple VaR constraints are more effective in reducing tail risk than those based on a single VaR constraint.     

Portfolio selection with mental accounts and background risk

Das et al. (2010) develop a model where an investor divides his or her wealth among mental accounts with motives such as retirement and bequest. Nevertheless, the investor ends up selecting portfolios within mental accounts and an aggregate portfolio that lie on the mean–variance frontier. Importantly, they assume that the investor only faces portfolio risk. In practice, however, many individuals also face background risk. Accordingly, our paper expands upon theirs by considering the case where the investor faces background risk. Our contribution is threefold. First, we provide an analytical characterization of the existence and composition of the optimal portfolios within accounts and the aggregate portfolio. Second, we show that these portfolios lie away from the mean–variance frontier under fairly general conditions. Third, we find that the composition and location of such portfolios can differ notably from those of portfolios on the mean–variance frontier.     

Portugal’s banking and financial crises: unexpected consequences of monetary integration?

Portugal’s current financial crisis might be related to a banking crisis resulting from joining the Euro. The new-currency eliminated the exchange rate risk, but not the credit or liquidity risks within the Euroarea. However, Portuguese banks acted as if all of these risks had disappeared. They began pumping money in Portugal, by borrowing intensively in Euros abroad at low interest rates. The ensuing liquidity generated a capital-flow bonanza boom that culminated in a bust phase. Private and sovereign debt dramatically increased, which further soared when the government rescued banks. Portugal was then compelled to take extreme measures to address extraordinary debt-levels.     

Optimal delegated portfolio management with background risk

Most investors delegate the management of a fraction of their wealth to portfolio managers who are given the task of beating a benchmark. However, in an influential paper [Roll, R., 1992. A mean/variance analysis of tracking error. Journal of Portfolio Management 18, 13–22] shows that the objective functions commonly used by these managers lead to the selection of portfolios that are suboptimal from the perspective of investors. In this paper, we provide an explanation for the use of these objective functions based on the effect of background risk on investors’ optimal portfolios. Our main contribution is to provide conditions under which investors can optimally delegate the management of their wealth to portfolio managers.