Cet article examine l'evolution a court terme des cours du cacao sur le marche de New York. Nous essayons d'etablir des previsions hors echantillon en utilisant une modelisation non lineaire de type reseaux de neurones. Nous examinons aussi l'impact des volumes de transactions, de la volatilite...

The market’s line estimation implicitly assumes that its parameters are constant over time. Investors, who use the beta of this line for build their portfolio, have a similar behavior whatever their investment horizon. We discuss this hypothesis in this article using the technique of wavelets...

The CAPM theory provides a measure of the sensitivity of an asset to the market called the systematic risk. The Beta of equity is estimated by its market line. According to the OLS hypothesis, it is stable over time but this is not empirically verified. Many studies are in favour with this fact...

The Beta coefficient theorized by the CAPM is estimated by the Market Line. By hypothesis, the Beta is stable over time but empirical studies on it volatility don't confirm this fact. One of them is related to with agent heterogeneity hypothesis. In this paper; we study this hypothesis by...

The Rolling-Regression are currently used to study the parameters stability over time. In finance, we can analyse the time evolutions of systematic risk relaxing the constant-Beta hypothesis. This method can be associated with a wavelet decomposition of the variables in order to the parameters...