In this paper we analyze the determinants of capital depreciation, from a quantitative point of view, with an application to the Spanish economy. In the light of the scarce literature on this subject, we formulate some testable hy-pothesis in identifying a set of economic variables which grasp the impact of the different factors influencing such depreciation. The empirical results show that obsolescence, in both technological and structural senses, is the main factor explaning the severe capital destruction experienced, from the mid-seventies up to the mid-eighties, in the private non-financial sector of the Spanish economy.

Keywords: depreciation, obsolescence, endogenous capital, cointegration.