Economists of the 20th century paid little attention to the labour share, probably because the the labour share was thought to be constant over time and across countries. However, recent data refute this hypothesis. Hence, in recent years, economists have been increasingly concerned with the determination of factor shares. We study two aspects not explored yet : the relationship between the labour share and the distribution of personal incomes and the effect of education on the labour share. We start by putting together the existing data on country labour shares. This analysis shows that measuring the labour share is a difficult exercise and that the choice of data and adjustment affects both country ranking and movements over time within a country. We then build a general equilibrium model in which income inequality and the sharing of value-added are correlated through the equilibrium labour supply. We find an ambiguous relationship between the labour supply and the labour share which depends on the elasticity of substitution between capital and labour. On the other hand, our cross-country and panel evidence over the period 1960-1990 shows that a larger labour share is associated with lower inequality. Our next concern is the effect of education on the labour share. We study a two-sector model where workers are heterogenous with respect to their level of schooling and where firms have monopsony power due to search frictions. The more educated an agent is, the more job offers she may receive. Higher education raises wage competition among employers, and hence, wages obtained by high-educated workers, which implies that the labour share is increasing in the proportion of high-educated individuals. Lastly, we examine the role that education has played in determining the labour share using a panel of OECD countries over the period 1970-2000. Our results indicate that an increase in the proportion of high-educated workers leads to an increase in the labour share.

La question du partage de la valeur ajoutée entre revenus du travail et revenus du capital est abordée dans de nombreuses analyses concernant la croissance ou les inégalités. Mais la littérature économique fournit peu d'indications sur le partage qui pourrait être "optimal", par exemple pour dynamiser la croissance. Le diagnostic sur l'orientation du partage de la valeur ajoutée dépend de l'indicateur retenu. De 1990 à 2007, dans le périmètre des sociétés non financières, ce partage fluctue en France autour d'un niveau qui paraît stabilisé alors que la part des salaires diminue dans certains pays, comme l'Allemagne, ou augmente dans d'autres, comme l'Italie. Parallèlement à ces évolutions, la part des revenus salariaux les plus élevés a partout nettement augmenté. La décomposition de la part du capital révèle également d'importants mouvements. Finalement, depuis 2008, le partage a connu des évolutions différenciées selon les pays. Malgré une érosion du taux de marge, on observe en France une résistance particulière des revenus de la propriété.