In this paper we study the determinants of intangible assets from the viewpoint of financial theory. We develope an explanatory model of intangible assets investment, which is then estimated later using panel data from a sample of non-financial Spanish firms. In contrast to the models developed for tangible assets investment, our model controls the industry-specific effect, which is relevant for this kind of investment, as our results also confirm. On the one hand, the empirical evidence obtained corroborates that cash flow is an important determinant of intangible assets investment. On the other, the results confirm that firms with a larger proportion of intangible asset have less debt. Moreover, we find that firms materialize their investment opportunities in both tangible and intangible assets. Finally, the empirical evidence shows the existence of scale economies for investment in intangible assets.

Key words: intangible assets, financial theory, asymmetric information, cash flow.
JEL classification: G31, G32.