Résumé en français

This paper studies the influence of two properties of interdependence – magnitude and relative asymmetry- on the buyer's control on its supplier. Four dimensions of control are examined: the objects of the control (results, working processes, behaviours and supplier characteristics), the means of the control (market, organisation, social control), the influence strategies (more or less coercive), and also the reaction of the supplier. The research is based on a case study conducted within an equipment component maker and its supplier in the automobile industry. The study shows that the modes of control used by the buyer firm depends on the power-dependence relationship with its supplier. Moreover, the development of interpersonal relationships seems to be a strategy of informal control for the dominated party.