Weighted norm inequalities and hedging in incomplete markets

Let be an -valued special semimartingale on a probability space with canonical decomposition . Denote by the space of all random variables , where is a predictable -integrable process such that the stochastic integral is in the space of semimartingales. We investigate under which conditions on the semimartingale the space is closed in , a question which arises naturally in the applications to financial mathematics. Our main results give necessary and/or sufficient conditions for the closedness of in . Most of these conditions deal with BMO-martingales and reverse H?lder inequalities which are equivalent to weighted norm inequalities. By means of these last inequalities, we also extend previous results on the F?llmer-Schweizer decomposition.     

Linear Accounting Valuation When Abnormal Earnings Are AR(2)

The Ohlson (1995) model assumes that abnormal earnings follow an AR(1) process primarily for reasons of mathematical tractability. However, the empirical literature on the Garman and Ohlson (1980) model finds that the data support an AR(2) lag structure for earnings, book values and dividends. Moreover, the AR(2) process encompasses a far richer variety of time series patterns than does the AR(1) process and includes the AR(1) process as a special case. This paper solves the Ohlson model directly for an AR(2) abnormal earnings dynamic. The model is estimated on a time series firm-level basis following the approach used by Myers (1999). It is found that, like the Ohlson AR(1) model, the Ohlson AR(2) model severely underestimates market prices even relative to book values. These results further bring into question the empirical validity of the Ohlson model.     

Self-Insurance, Self-Protection and Market Insurance within the Dual Theory of Choice

As demonstrated by Ehrlich and Becker [1972], Expected Utility Theory predicts that market insurance and self-insurance are substitutes, whilst surprisingly, market insurance and self-protection could be complements. This article examines the robustness of this conclusion, as well as its extensions under the Dual Theory of Choice [Yaari, 1987]. In particular, the non-reliability of self-insurance activities, background risk and asymmetric information are considered.     

The level and quality of Value-at-Risk disclosure by commercial banks

In this paper we study both the level of Value-at-Risk (VaR) disclosure and the accuracy of the disclosed VaR figures for a sample of US and international commercial banks. To measure the level of VaR disclosures, we develop a VaR Disclosure Index that captures many different facets of market risk disclosure. Using panel data over the period 1996–2005, we find an overall upward trend in the quantity of information released to the public. We also find that Historical Simulation is by far the most popular VaR method. We assess the accuracy of VaR figures by studying the number of VaR exceedances and whether actual daily VaRs contain information about the volatility of subsequent trading revenues. Unlike the level of VaR disclosure, the quality of VaR disclosure shows no sign of improvement over time. We find that VaR computed using Historical Simulation contains very little information about future volatility.     

Short Selling and the Weekend Effect in Nasdaq Stock Returns

We examine daily short selling of Nasdaq stocks to explore whether speculative short selling causes a significant portion of the weekend effect in returns. We identify a weekend effect in speculative short selling whereby it constitutes a larger percentage of trading volume on Mondays versus Fridays. We find an opposite effect in dealer short selling, consistent with market makers adding liquidity and stability. Our main finding is that speculative short selling does not explain an economically meaningful portion of the weekend effect in returns, even among the firms most that are most actively shorted. This finding contradicts some prior studies.     

Testing for convergence of the Okun’s Law coefficient in Europe

Without convergence of macroeconomic parameters representative of the nature of adjustment mechanisms, even a common shock to members of a monetary union can lead to different macroeconomic consequences across the union and, eventually, to the need for more or less co-ordinated specific policies. In this paper, we test for the presence of convergence of the Okun’s Law coefficient (OLC) among several alternative groupings of European economies. The empirical strategy adopted is based on the evaluation of the time path of rolling regression estimates of the OLC for European countries. We then use a testing procedure suggested by Evans [Evans P (1996) J Econ Dynam Control 20:1027–1049] to investigate the convergence, or non-convergence, of the OLC in several groups of European countries by examining how the cross-country variance of the OLC evolves over time in these groups. A hypothesis of medium-term convergence of the OLC is rejected for most of the European country groups examined.      

Are there pecuniary compensations for working conditions?

In this paper we assess the relative contribution of working conditions to wage determination with an emphasis on differences along the earnings distribution. A survey of British employees in 2001 rich in questions regarding the job post enables us to separate the contribution of working conditions, job attributes and individual characteristics to the process of wage determination. Standard wage equations reveal that covariates such as having “repetitive job” and using generic skills such as “literacy” or “customer handling skills” are associated with significant premiums and penalties. Quantile regressions confirm the presence of penalties to poor working conditions, such as “working to tight deadlines”, that are significant in the middle section of the earnings distribution and robust to the inclusion of a wide range of controls for person, firm and other job characteristics. Counterfactual decompositions at quantiles show that, despite the apparent penalty, there are pecuniary compensations to poor working conditions around the first quartile and the median of the earnings distribution.     

Multigeneration innovation diffusion and intergeneration time: A cautionary note

A recent JAMS article reported the following finding: the longer the time between the launch of two adjacent generations in the same product category, the lower the initial rate of adoption of the later generation but the higher its subsequent rate of growth. This note shows that these results could be a method artifact, since they vanish once one controls for differences in the length of the data series used to compute the initial and subsequent rates of growth. So, for the time being, it is premature to accept these intergeneration effects as genuine. Christophe Van de Bulte (Ph.D., Pennsylvania State University) (vdbulte@wharton.upenn.edu) is an assistant professor of marketing at the Wharton School of the University of Pennsylvania. He holds an undergraduate degree in applied economics from the University of Antwerp, Belgium, and is a Fellow of the Belgian American Educational Foundation.His research focuses on new product diffusion and on the role of social networks in marketing settings, and has been published in theAmerican Journal of Sociology, theJournal of Marketing, Management Science, Marketing Science, and other journals. He serves on the editorial boards of theJournal of Business-to-Business Marketing andMarketing Science.     

Repurchasing Shares on a Second Trading Line

This paper studies a unique buyback method allowing firms toreacquire their own shares on a separate trading line whereonly the firm is allowed to buy shares. This share repurchasemethod is called the Second Trading Line and has been extensivelyused by Swiss companies since 1997. This type of repurchaseis unique for two reasons. First, unlike open market programs,the repurchasing company does not trade anonymously. Second,all transactions made by the repurchasing firm are publiclyavailable in real time to every market participant. This isa case of instantaneous disclosure which contrasts sharply withother markets characterized by delayed or no disclosure. Wedocument that the daily repurchase decision is statisticallyassociated with short-term price changes and the release offirm-specific news. We also find that repurchases on the secondtrading line have a beneficial impact on the liquidity of repurchasingfirms. Exchanges and regulators may consider the second tradingline an attractive share reacquisition mechanism because ofits transparency and positive liquidity effects.