This article presents Multivariate Logit (MVL) and Probit (MVP) models, which make it possible to analyse simultaneous purchases and relax the restrictive hypothesis that utility maximization leads to a single choice. These models enable a deeper analysis of competitive dynamics in a given category (variety seeking, complementarity, substitutability). The MVL model using a random parameter specification is illustrated in relation to the chocolate category. We underline the advantages and limitations of these models and propose new research avenues.