Complete and incomplete markets with short-sale constraints

Summary. This paper argues that the introduction of a short-sale constraint in the Arrow-Radner framework invalidates standard definitions of complete and incomplete markets. Two threshold values with familiar properties arise in this constrained set-up. If short sales are not allowed on some security, then financial markets will be incomplete in the standard sense. Beyond a particular level of the short-sale bound, financial markets are “complete”, since the short-sale constraint is not effective. For intermediate bounds the distinction between complete and incomplete financial markets is blurred. Although some technical definitions hold, agents can not fully transfer wealth among states. These intermediate cases, called “technically incomplete markets”, exhibit interesting welfare properties. For instance, the resulting equilibrium allocations may not be Pareto-dominated by those of the non-restricted complete markets equilibrium. Received: November 28, 2000; / revised version: November 9, 2001     

Optimal exploration investments under price and geological‐technical uncertainty: a real options model

This article develops a real options model for valuing natural resource exploration investments (e.g. oil or copper) when there is joint price and geological‐technical uncertainty. After a successful several‐stage exploration phase, there is a development investment and an extraction phase. All phases are optimized contingent on price and geological‐technical uncertainty.
Several real options are considered. There are flexible investment schedules for all exploration stages and a timing option for the development investment. Once the mine is developed, there are closure, opening and abandonment options for the extraction phase. Our model maintains a relatively simple valuation structure by collapsing price and geological‐technical uncertainty into a one‐factor model.
We apply the model to a copper exploration prospect and find that a significant fraction of total project value is due to the operational, development and exploration options available to project managers.     

Derived versus full name brand extensions

Most brand extension studies follow the assumption that brand extensions use the full original parent brand name (e.g., Oral-B tooth brush may extend to Oral-B dental floss). However, some companies use derived brand names in their brand extension strategies (e.g. Nestea Iced Tea). This study explores the advantages and disadvantages of derived brand extensions compared to full name extensions. The study examines the importance of target market effects on the evaluation of both brand extension strategies. Findings support the idea that derived brand names leverage parent brand evaluations and protect parent brand from extension failures.     

Networks of queues with infinite servers in each node applied to the management of a two echelons repair system

After a report of results about infinite servers queues, essentially on its busy period, a model is built, using networks of queues with infinite servers in each node, to study a two echelons repair system for example of a fleet of aircraft, shipping or trucks. The customers are the failures, and their service time is the time that goes from the instant at which they occur till they are completely repaired. The failing repairs occur in a base or in a remote station. The whole failures detected in the base are repaired there. Some of the failures detected in the station are repaired there and the others in the base. The results referred above allow the determination of a two echelons repair system performance measures. In this application, models of Carrillo （1991） and Ferreira （1996） are considered, improved and completed. The theory is illustrated with a numerical example.     

Optimal close-to-home biases in asset allocation

This article studies optimal portfolio decisions with (long-term) liabilities for small open economy based investors, including the optimality of currency hedging (Walker (2008a). Chile is the home country of the representative investor, but results are likely to hold more generally. The problem is set up as in [Sharpe & Tint, 1990] and [Hoevenaars et al., 2007]. Hedging the liabilities and the consumption currency may imply optimal close-to-home biases, defined as overweighting asset classes which are highly correlated with local ones. The implementation challenges include: developing a methodology to estimate expected returns in local (real) currency; estimating the covariance matrix allowing for serial and crossed-serial correlations; and checking the results' robustness using a resampling method. The findings are: (i) portfolios always have optimal close-to-home biases, beyond the investment in local fixed income to hedge liabilities; (ii) currency hedging reduces investment in close-to-home asset classes, (iii) but has ambiguous effects on welfare — detected with the resampling method; (iv) currency hedged long-term US bonds are useful for hedging local interest rate risk; and (v) liabilities give access to high risk-return portfolios, not affecting otherwise the overall shape of the efficient regions. This article can be useful to investors based on small open economies, including pension funds, insurance companies, sovereign wealth funds and Central Banks.