Approximate maximum likelihood estimation for stochastic differential equations with random effects in the drift and the diffusion

Consider N independent stochastic processes \((X_i(t), t\in [0,T])\), \(i=1,\ldots , N\), defined by a stochastic differential equation with random effects where the drift term depends linearly on a random vector \(\Phi _i\) and the diffusion coefficient depends on another linear random effect \(\Psi _i\). For these effects, we consider a joint parametric distribution. We propose and study two approximate likelihoods for estimating the parameters of this joint distribution based on discrete observations of the processes on a fixed time interval. Consistent and \(\sqrt{N}\)-asymptotically Gaussian estimators are obtained when both the number of individuals and the number of observations per individual tend to infinity. The estimation methods are investigated on simulated data and show good performances.     

What do we know about consumers' ontological security in disaster scenarios?

While prior consumer studies have adopted various theoretical perspectives to explain individuals' reactions to disasters, scant attention has been paid to the role of ontological security in shaping those responses. This study attempts to fill this knowledge gap by qualitatively exploring ontological security in two contexts: man-made and natural disasters. To this end, we conducted 35 focus groups in the UK, Germany, and France to address how people reacted to terrorist attacks and the COVID-19 pandemic respectively. Through thematic analysis, three themes emerged: fear versus anxiety, oneself versus others, and materialistic versus experiential purchases. Man-made disasters appear to elicit fear, concern for self, and a preference for materialistic purchases, whereas natural disasters seem to trigger anxiety, concern for others, and a preference for experiential purchases. Both types of disasters seem to evoke a desire to escape from reality. In closing, we discuss both transitory and prolonged threats to ontological security and how they shape individuals' behaviours while restoring their security.     

Stock Recommendations in Swedish Printed Media: Leading or Misleading?

Abstract

This paper analyses the initiated and changed recommendations published in six well-known Swedish newspapers and business magazines for the period 1996–2000 using a buy-and-hold abnormal returns (BHARs) approach. The results distinguish between recommendations from analysts and journalists. Buy recommendations were misleading investors, whereas sell recommendations were leading them correctly, overall yielding returns in line with the market. This asymmetry is due to positive information from the management of the company being more intricate to interpret than negative. Both good and bad information provided by the management is generally positively biased, a phenomenon influencing both analyst and journalist recommendations. Following buy and sell recommendations from analysts yielded BHARs in line with those from journalists, which in turn generates returns in line with their peers. Going short in the recommended stocks, irrespective of type and origin, would lead to a 24-month BHAR of 14%.     

Has the CSR engagement of electrical companies had an effect on their performance? A closer look at the environment

Even though electrical companies attain a top ranking in the publication of CSR reports, they are often accused of 'green‐washing' due to their bad environmental reputation. The current economic crisis is testing their real CSR commitment more than ever, especially when this goes beyond its economic consequences. Based on a worldwide sample of electrical companies, we are going to study why companies are being socially responsible. We wish to know if it is due to the impact on the firms' performance or whether there are other motives (legitimation, improving their reputation) that lead companies to carry out these practices. We will also consider if it changes across the kind of CSR action considered. The results show that there is an economic justification beyond the socially responsible behaviour of the electrical companies. Additionally, most kinds of CSR action (community, diversity, corporate governance, product responsibility) are also carried out looking for economic rewards. However, the CSR actions oriented to the environment are mainly motivated by their need to improve their image and reverse their negative impact. Copyright © 2014 John Wiley & Sons, Ltd and ERP Environment