We include simultaneously both realized volatility measures based on high-frequency asset returns and implied volatilities backed out of individual traded at the money option prices in a state space approach to the analysis of true underlying volatility. We model integrated volatility as a...

The shortage function has recently been introduced in portfolio selection theory for measuring efficiency. In this paper we focuss on the case of shortselling. We show that, in such a case, the shortage function can be computed in closed form. Some issues concerning duality are also analyzed. We...

We provide empirical support for the conventional wisdom that there are times when optimistic investors tend to build their hopes into castles in the air, and pay a large premium over intrinsic value for stocks of firms in the early stages of their life cycles with perceived growth...

This paper empirically examines the relationship between trading volume and conditional volatility of returns in the Tunisian stock market within the framework of the mixture of distribution hypothesis (MDH) and the sequential information arrival hypothesis (SIAH). Through this study, we...

This paper is the first to determine the effect that media sentiment has on stock returns for UK companies and tests whether there is any return predictability contained in the UK media sentiment data. We show that measures of positive and negative media sentiment have significant relationships...

This paper studies the dynamics of stock market volatility and retail investor attention measured by internet search queries. We find a strong co-movement of stock market indices' realized volatility and the search queries for their names. Furthermore, Granger causality is bi-directional: high...

This paper studies the dynamics of stock market volatility and retail investor attention measured by internet search queries. We find a strong co-movement of stock market indices' realized volatility and the search queries for their names. Furthermore, Granger causality is bi-directional: high...

Stock and Treasury bond comovement, volatilities, and their relations to their price valuations and fundamentals change stochastically over time, both in magnitude and direction. These stochastic changes are explained by a general equilibrium model in which agents learn about composite economic...

We investigate a link between the performance of several security indexes in broad investment categories and investor attention as measured by Google search probability. We find that there is a significant short-term change in index returns following an increase in attention. Conversely, a shock...

This article aims to highlight the implications of liquidity crises in the context of emerging capital market. Capital markets, and especially emerging capital market appear to behave notably differently during periods of liquidity crises in comparison with periods of stability. The concept of...