Alain François-heude MRM, University of Montpellier   University of Montpellier 2 (CC28) Sciences et Techniques du Languedoc Place Eugène Bataillon Montpellier Cedex 5, 34095 France   Alain.Francois-Heude@univ-montp2.fr             JEL Areas: G1 : General Financial Markets: General (includes Measurement and Data) D4 : Market Structure and Pricing: General