In this paper, we use a dual approach based on cost functions to analize the effects of private capital and infrastructures on the industrial productive performance of Spanish regions. We find that the shadow prices of private capital are generally high and bigger than the user cost, and that the shadow prices of public infrastructures are positive. In these circunstances, the correction of technical progress measurement, allowing for the direct and indirect effects of the dynamics of fixed factors, points to the existence of important private capital restrictions that began to be corrected only in the last five years of the 1980-1993 period. The public sector has reduced, albeit not completely, the initial relative scarcity of infrastructures. Finally, our results indicate that, on average, both types of capital reduce the use of intermediate inputs and have a considerable positive impact on employment, although with significant exceptions in some regions.

Keywords: infrastructures, private capital, cost, productivity.
JEL classification: H54, H72, O47.