This paper addresses the issue of socio-economic stratification of Latin American markets, and specifically that of Argentina. Transformations of the last decade have modified the regional scenario and have significantly altered the economic and socio-demographic structures. The authors argue that the current problems that the classification and stratification systems present today do not deal with their reliability or comparability, but - in an even more serious, basic and deeper dimension - with their validity. What has lost validity is the basic representation model of the socio-economic structure and of the rules of its dynamics. Market stratification based on 'hard' indicators is no longer applicable to the realities that are today - to state mildly - 'soft', and the logic of the mobility of which has been profoundly altered and overshadowed, adopting chaotic characteristics.