The economie literature largely defends the existence of financial supports to private R&D owing to the numerous externalities and distortions that lead firms to underinvest in R&D. The proliferation of these supports at different territorial levels and the recent emergence of more constrasting arguments concerning their rationale underline an increasing need for the analysis of these policies and the ir territorial impacts. The purpose of this PhD thesis is to provide new elements regarding the rationale, the effects and the effectiveness of financial supports to private R&D.The first chapter proposes a discussion on the ratio na le of financial supports to business R&D following the endogenous growth literature and its refinements including a geographical dimension. Divergences in the theoretical and empirical approaches concerning the origins and the magnitude of the private underinvestment in R&D eventually leads to the hypothesis of a limited and specifie private underinvestment in R&D.Chapters 2 and 3 provide theoretical analyses of the spatial and dynamics effects of a centralized subsidy policy for R&D. The results show that this policy strengthens economie growth, reduces territorial inequalities while improving the global welfare. The benefits of such policy are not only dependent on the chosen assumption about returns to R&D but more importantly on its design in terms of funding and geographical allocation of subsidies.Chapter 4 provides an empirical analysis of the capacity of financial supports to R&D to stimulate private investment in R&D from a panel of OECD countries.The results indicate a greater sensitivity of private investment in R&D to indirect supports (fiscal incentives) than to direct supports (grants and subsidies) and suggest the existence of substitution effects between these two forms of support.
