Knowledge that Transforms

We examine the behavior of common stock prices after a large change in price occurs during a single trading day and find evidence that the stock market appears to have overreacted, especially in the case of price declines; however, the magnitude of the overreaction is small compared to the bid-ask spreads observed for the individual stocks in the sample. We interpret this finding as being consistent with a market that is efficient after transactions costs are considered.

This paper suggests a modification to the explicit finite difference method for valuing derivative securities. The modification ensures that, as smaller time intervals are considered, the calculated values of the derivative security converge to the solution of the underlying differential equation. It can be used to value any derivative security dependent on a single state variable and can be extended to deal with many derivative security pricing problems where there are several state variables. The paper illustrates the approach by using it to value bonds and bond options under two different interest rate processes.

David Heath, Robert Jarrow, Andrew Morton, Bond Pricing and the Term Structure of Interest Rates: A Discrete Time Approximation, The Journal of Financial and Quantitative Analysis, Vol. 25, No. 4 (Dec., 1990), pp. 419-440

Recent research finds that the prior period's worst stock return performers (losers) outperform the prior period's best return performers (winners) in the subsequent period. This potential violation of the efficient markets hypothesis is labeled the “overreaction” phenomenon. This paper shows that the tendency for losers to outperform winners is not due to investor overreaction, but to the tendency for losers to be smaller-sized firms than winners. When losers are compared to winners of equal size, there is little evidence of any return discrepancy, and in periods when winners are smaller than losers, winners outperform losers.

Anup Agrawal, Gershon N. Mandelker, Large Shareholders and the Monitoring of Managers: The Case of Antitakeover Charter Amendments, The Journal of Financial and Quantitative Analysis, Vol. 25, No. 2 (Jun., 1990), pp. 143-161

Most asset pricing models postulate a positive relationship between a stock portfolio's expected returns and risk, which is often modeled by the variance of the asset price. This paper uses GARCH in mean models to examine the relationship between mean returns on a stock portfolio and its conditional variance or standard deviation. After estimating a variety of models from daily and monthly portfolio return data, we conclude that any relationship between mean returns and own variance or standard deviation is weak. The results suggest that investors consider some other risk measure to be more important than the variance of portfolio returns.

In rational, efficiently functioning markets, the returns on stock index and stock index futures contracts should be perfectly, contemporaneously correlated. This study investigates the time series properties of 5-minute, intraday returns of stock index and stock index futures contracts, and finds that S&P 500 and MM index futures returns tend to lead stock market returns by about five minutes, on average, but occasionally as long as 10 minutes or more, even after stock index returns have been purged of infrequent trading effects; however, the effect is not completely unidirectional, with lagged stock index returns having a mild positive predictive impact on futures returns.

Standard statistical auditing procedures rest upon the assumption that statistical nonsampling errors do not exist. Three distinct types of statistical nonsampling errors have been identified in the literature. This paper presents new theoretical results regarding the problem of audit sampling in the presence of nonsampling errors of the first type. When nonsampling errors of the first type exist, standard statistical auditing procedures yield a negatively biased estimate of the true number of errors and dollar amounts associated with those errors. A double‐audit sampling plan is introduced here and provides an unbiased estimate of the true number of errors and dollar amounts of those errors in the presence of nonsampling errors of the first type. A new concept of auditor reliability also is defined, and results analogous to those in classical measurement theory are developed for the case of nonsampling errors of the first type. The multiple auditor results reported in a previous study are reanalyzed to give an estimate of the true number of problems and an estimate of auditor reliability in a complex auditing task. Résumé. Les procédés de vérification statistiques standard reposent sur l'hypothèse selon laquelle les erreurs non dues au sondage statistique n'existent pas. Trois catégories distinctes d'erreurs statistiques autres que celles d'échantillonnage sont identifiées dans la documentation existante. Les auteurs proposent de nouveaux résultats théoriques concernant le problème de vérification par sondages en présence d'erreurs non dues au sondage appartenant à la première de ces trois catégories. Lorsqu'il existe des erreurs non dues au sondage appartenant à cette première catégorie, les procédés de vérification statistiques standard livrent une estimation négativement biaisée du nombre véritable d'erreurs et des valeurs monétaires associées à ces erreurs. Le double plan de vérification par sondages proposé ici offre une estimation non biaisée du nombre d'erreurs véritable et des valeurs monétaires correspondant à ces erreurs en présence d'erreurs non dues au sondage appartenant encore une fois à la première catégorie. Les auteurs définissent également une nouvelle notion de fiabilité du vérificateur et mettent au point des résultats analogues à ceux que permet d'obtenir la théorie classique de mesure, pour les cas d'erreurs non dues au sondage appartenant à ladite première catégorie. Ils procédent à une nouvelle analyse des résultats multiples dont il est fait état dans une étude effectuée par d'autres auteurs, cela afin d'obtenir une estimation du nombre de problèmes véritable et une évaluation de la fiabilité du vérificateur dans une tâche de vérification complexe.

Building on the notion that both earnings surprises and the level of insider trading are noisy signals of future prospects of the firm, this paper empirically investigates joint informativeness of the two signals surrounding earnings announcements. Classification of a large sample of firms in the time period 1977–81 based both on the levels of earnings surprise and insider trading results in a finer partition informationally, compared to using just one signal. Both additive and interactive effects are observed while analysing the security market response during the three trading days centered on the day of earnings announcements. Over a 19‐day postannouncement period, the results are less pronounced. The overall pattern of results implies that each signal may contain information not contained in the other, and/or some of the noise associated with each signal may be interactively resolved at the time of earnings announcements. This inference is robust under many measurement alternatives. Résumé. À partir du principe voulant que les bénéfices imprévus ainsi que l'importance des opérations d'initiés soient des indicateurs manifestes des perspectives futures de l'entreprise, les auteurs procèdent à une étude empirique de la qualité informative conjointe des deux indicateurs dans le cadre des avis de bénéfices. La classification d'un vaste échantillon d'entreprises pendant la période 1977–1981 en fonction à la fois du niveau des bénéfices imprévus et de l'importance des opérations d'initiés permet un découpage plus subtil sur le plan informationnel que l'utilisation d'un indicateur unique. Les auteurs observent les effets tant additifs qu'interactifs de cette classification dans l'analyse de la réponse du marché boursier au cours des trois jours de bourse centrés sur le jour de la communication des avis de bénéfices. Pour la période de 19 jours suivant la période d'avis, les résultats sont moins accusés. Le modèle global des résultats suppose que chaque indicateur peut livrer de l'information que l'autre ne livre pas et qu'une partie de ce que manifeste chaque indicateur peut être résolue de façon interactive au moment de la communication des avis de bénf́ices. Cette induction résiste à l'épreuve de plusieurs techniques de mesure.

This paper examines accounting change decisions in Canada. Evidence gathered from financial statements suggests that there is a relation between bond covenants and the decision to make an accounting policy change. Except for the effect of regulation, the political visibility hypothesis did not hold.