Market Efficiency and Behavioral Finance: non correlation between Risk - Profitability on Antipodal Markets

: Le prix Nobel d'economie a ete decerne en 2013 a deux theories opposees en finance de marche. Pour E. Fama et L.P. Hansen, les marches sont « parfaits » car ils detiennent toute l'information en continu. Il devient ainsi impossible de survaloriser la performance du tracker. Mais pour R. Shiller, ce presuppose rationaliste est rejete au profit d'une finance comportementale. Notre recherche allie ces deux theories opposees. Notre etude empirique des marches antipodiques sur cinq ans, puis notre modele de comportement, montrent qu'avec une information certaine (variation du Dow Jones), la rentabilite du tracker Cac40 est demultipliee sans risque. Abstract: The Nobel Prize in Economics was awarded in 2013 to two competing theories in Finance. For E. Fama and L.P. Hansen, the markets are efficient as they hold all the information continuously. This makes it not possible to overrate the tracker performance. For R. Shiller, this rationalist assumption is rejected in favor of a behavioral finance. Our research combines these two opposing theories, our em-pirical study of antipodal markets over five years and our behavior model show that with some information (Dow Jones daily variation), profitability of Cac40 tracker is multiplied without risk.