Abstract In this article we develop a model to analyze patent-protected R&D investment projects when there is (imperfect) competition in the development and marketing of the resulting product. The competitive interactions that occur substantially complicate the solution of the problem since the decision maker has to take into account not only the factors that affect her/his own decisions, but also the factors that affect the decisions of the other investors. The real options framework utilized to deal with investments under uncertainty is extended to incorporate the game theoretic concepts required to deal with these interactions. Implementation of the model shows that competition in R&D, in general, not only increases production and reduces prices, but also shortens the time of developing the product and increases the probability of a successful development. These benefits to society are countered by increased total investment costs in R&D and lower aggregate value of the R&D investment projects.

We contribute to the debate over the reform of the Basel Accord by developing risk-based capital requirements for mortgage loans held in portfolio by financial intermediaries. Our approach employs simulation of both economic variables that affect default incidence and conditional loss probability distributions. Results indicate that appropriate capital charges for credit risk vary substantially with loan characteristics and portfolio geographic diversification. Hence, rules that offer little risk differentiation, including the current Basel I regime and “standardized” approach proposed in Basel II result in significant divergence between regulatory and economic capital. These results highlight the incentive problems inherent in simplified methods of capital regulation.

This paper analyzes the role health status plays in household portfolio decisions using data from the Health and Retirement Study. The results indicate that health is a significant predictor of both the probability of owning different types of financial assets and the share of financial wealth held in each asset category. Households in poor health are less likely to hold risky financial assets, other things (including the level of total wealth) being the same. Poor health is associated with a smaller share of financial wealth held in risky assets and a larger share in safe assets. We find no evidence that the relationship between health status and portfolio allocation is driven by “third variables” that simultaneously affect health and financial decisions. Further, the relationship between health status and portfolio choice does not appear to operate through the effect of poor health on individuals’ attitudes toward risk, their planning horizons, or their health insurance status.

Abstract We assert that the tax expense is a powerful context in which to study earnings management, because it is one of the last accounts closed prior to earnings announcements. Although many pre‐tax accruals must be posted in the year‐end general ledger, managers estimate and negotiate tax expense with their auditors immediately prior to earnings announcements. We hypothesize that changes from third‐ to fourth‐quarter effective tax rates (ETRs) are negatively related to whether and how much a firm's earnings absent tax expense management miss analysts' consensus forecast, a proxy for target earnings. We measure earnings absent tax expense management as actual pre‐tax earnings adjusted for the annual ETR reported at the third quarter. We provide robust evidence that firms lower their projected ETRs when they miss the consensus forecast, which is consistent with firms decreasing their tax expense if non‐tax sources of earnings management are insufficient to achieve targets. We also find that firms that exceed earnings targets increase their ETR, but this effect is less significant. By studying the tax expense in total, rather than narrow components of deferred tax expense, our results provide general evidence that reported taxes are used to manage earnings.

Advances in communication and transportation technologies have the potential to bring people closer together and create a “global village.” However, they also allow heterogeneous agents to segregate along special interests, which gives rise to communities fragmented by type rather than by geography. We show that lower communication costs should always decrease separation between individual agents even as group-based separation increases. Each measure of separation is pertinent for distinct types of social interaction. A group-based measure captures the diversity of group preferences that can have an impact on the provision of public goods. While an individual measure correlates with the speed of information transmission through the social network that affects, for example, learning about job opportunities and new technologies. We test the model by looking at coauthoring between academic economists before and during the rise of the Internet in the 1990s.

Most papers that employ Differences-in-Differences estimation (DD) use many years of data and focus on serially correlated outcomes but ignore that the resulting standard errors are inconsistent. To illustrate the severity of this issue, we randomly generate placebo laws in state-level data on female wages from the Current Population Survey. For each law, we use OLS to compute the DD estimate of its “effect” as well as the standard error of this estimate. These conventional DD standard errors severely understate the standard deviation of the estimators: we find an “effect” significant at the 5 percent level for up to 45 percent of the placebo interventions. We use Monte Carlo simulations to investigate how well existing methods help solve this problem. Econometric corrections that place a specific parametric form on the time-series process do not perform well. Bootstrap (taking into account the autocorrelation of the data) works well when the number of states is large enough. Two corrections based on asymptotic approximation of the variance-covariance matrix work well for moderate numbers of states and one correction that collapses the time series information into a “pre”- and “post”-period and explicitly takes into account the effective sample size works well even for small numbers of states.

ABSTRACT Does valuation affect mergers? Data suggest that periods of stock merger activity are correlated with high market valuations. The naïve explanation that overvalued bidders wish to use stock is incomplete because targets should not be eager to accept stock. However, we show that potential market value deviations from fundamental values on both sides of the transaction can rationally lead to a correlation between stock merger activity and market valuation. Merger waves and waves of cash and stock purchases can be rationally driven by periods of over‐ and undervaluation of the stock market. Thus, valuation fundamentally impacts mergers.

The evolution of technology causes human capital to become obsolete. We study this phenomenon in an overlapping generations setting, assuming that technology evolves stochastically and that older workers find updating uneconomic. Experience and learning by doing may offer the old some income protection, but technology advance always turns them into has‐beens to some degree. We focus on the determinants (demand elasticities, persistence of technology change, etc.) of the severity of the has‐beens effect. It can be large, even leading to negatively sloped within‐occupation age‐earnings profiles and an occupation dominated by a few young, high‐income workers. Architecture displays the sort of features the theory identifies as magnifying the has‐beens effect, and both anecdotes and some data suggest that the has‐beens effect in architecture is extreme indeed.

ABSTRACT We examine whether the market interprets changes in dividends as a signal about the persistence of past earnings changes. Prior to observing this signal, investors may believe that past earnings changes are not necessarily indicative of future earnings levels. We empirically investigate whether a change in dividends alters investors' assessments about the valuation implications of past earnings. Results confirm the hypothesis that changes in dividends cause investors to revise their expectations about the persistence of past earnings changes. This effect varies predictably with the magnitude of the dividend change and the sign of the past earnings change.