The aim of this paper is to study the determinants of investment on material and immaterial assets of Spanish firms considering they are heterogeneous assets. With this objective, we propose an investment model based on both prospective models and Tobin’s q. The developed model is then applied to analyse the investment determinants of material and immaterial assets over a panel of 87 non-financial Spanish firms that have been quoting on the Stock Market during 12 years. Results show that material investment decisions are isolated from immaterial assets, whereas immaterial investment is affected by tangible investment and stock.

Keywords: Investment models, Assets Heterogeneity, Tobin’s q, Spanish Firms.

JEL Classification: D21, M21, M10