Tiago P. Filomena Management School, Federal University of Rio Grande do Sul, Porto Alegre, Brazil   Washington Luís Street, 855, office 309 - Centro Histórico Porto Alegre, RS 90010-460 Brazil   tiago.filomena@ufrgs.br             JEL Areas: G1 : General Financial Markets: General (includes Measurement and Data) C6 : Mathematical Methods and Programming: General