We investigate the decline of the labor share in a world characterized by rapid technological changes and increasing heterogeneity of capital assets. Our theoretical model allows for these assets to affect the labor share in different directions depending on the capital-labor substitution/complementary relationship and the workers’ skill level. We test the predictions of our model using a large cross-country, cross-industry data set, considering different forms of tangible and intangible capital inputs. Our results show that, over the 1970-2007 period, the decline of the labor share has been mainly driven by technical change and Information and Communication Technology (ICT) assets, mitigated by increasing investments in R&D based knowledge assets. Extending to other forms of intangible capital from 1995 onwards, we find that intangible investments related to innovation increase the labor share while those related to the organisation of firms contribute to its decline, particularly for the low and intermediate skilled workers. Our results are robust to an array of econometric issues, namely heterogeneity, cross sectional dependence, and endogeneity.