The usual development of the continuous time random walk (CTRW) assumes that jumps and time intervals are independent (and identically distributed) random variables. In this paper we address the theoretical setting of non-independent CTRW's where jumps and/or time intervals are correlated. An...

A log-normal random walk with parameters that are functions of market stress naturally accounts for volatility clustering and fat-tailed return distributions. Fitting this model to a stock and a bond index we find no evidence of significant misspecification despite the fact that the model has no...

This paper provides evidence on the random walk hypothesis in G7 stock price indices using unit root tests which allow for one and two structural breaks in the trend. Of the seven countries we find, at best, evidence of mean reversion in the stock price index of Japan. Thus, overall, our results...