Using a large set of daily US and Japanese stock returns, we test in detail the relevance of Student models, and of more general elliptical models, for describing the joint distribution of returns. We find that while Student copulas provide a good approximation for strongly correlated pairs of...

The aim of our work is to propose a natural framework to account for all the empirically known properties of the multivariate distribution of stock returns. We define and study a "nested factor model", where the linear factors part is standard, but where the log-volatility of the linear factors...

We revisit the "Smile Dynamics" problem, which consists in relating the implied leverage (i.e. the correlation of the at-the-money volatility with the returns of the underlying) and the skew of the option smile. The ratio between these two quantities, called "Skew-Stickiness Ratio" (SSR) by...

We find that when measured in terms of dollar-turnover, and once beta-neutralised and Low-Vol neutralised, the Size Effect is alive and well. With a long term t-stat of 5.1, the “Cold-Minus-Hot” (CMH) anomaly is certainly not less significant than other well-known factors such as Value or...

The vast majority of recent studies in market impact assess each product individually, and the interactions between their order flows are disregarded. This strong approximation may lead to an underestimation of trading costs and possible contagion effects. Transactions mediate a significant part...

We present extensive evidence that "Risk Premium" is strongly correlated with tail-risk skewness, but very little with volatility. We introduce a new, intuitive definition of skewness, and elicit a linear relationship between the Sharpe ratio of various risk premium strategies (Equity,...