We start from the empirical observation that unemployed migrants from Africa and Ex-Yugoslavia have more difficulties when trying to re-enter the labour market as compared to migrants from Portugal. Based on a unique dataset of newly unemployed individuals in the Swiss Canton of Vaud, we set out to analyse the reasons for the large difference in the length of unemployment spells by testing the most important theoretical approaches of employability proposed in the literature. First, we analyse whether differences at the level of individual resources explain differences in outcome (human capital). Second, we test how the size of the social network influences the likelihood of finding employment (social capital). Third, we account for motivation, effort and job search strategies (proactive search behaviour). Eventually, we controlled for individual wellbeing as a potential driver of unemployment duration but we found no evidence that these different factors are able to explain the underperformance of Ex-Yugoslavian and African respondents. Our conclusion is that discriminatory patterns related to nationality are at least in part responsible for the substantial disadvantage of these groups and we explain it by referring to the diffusion of negative stereotypes about specific immigrant communities in the public sphere.