Numerous empirical studies have shown evidence of nonlinearities in financial time series, which can be of both a deterministic and a stochastic nature. Chaos is an example of the former, and heteroscedasticity in the conditional variance an example of the latter. We apply a test, the BDS test,...

A "compass rose" pattern sometimes appears when stock returns are plotted against themselves with a one-day lag, since stock prices move in discrete steps. In this paper, we perform a Monte Carlo study on simulated stock price series rounded in different ways to mirror the behavior of stocks on...

In the early 50's, Markowitz introduced the modern portfolio selection theory which, to this very day, constitutes the basis of many investment decisions. Given different correlated assets, how does an investor create a portfolio maximizing the expected utility? Markowitz's contribution was to...

The continuous-state GARCH model is misspecified if applied to returns calculated from discrete price series. This paper proposes modifications of the above model for handling such cases. The focus is on the AR-GARCH framework, but the same ideas could be used for other stochastic processes as...