Relationship between debt, R&D and physical investment, evidence from US firm-level data

This paper is motivated by the hypothesis by Hall (1992) who claims that firms prefer to use debt to finance physical investment but not R&D, due to the risky nature of R&D. Employing a dynamic simultaneous approach and R&D Master File, the relationship between debt, R&D and physical investment is reestimated with the full sample and two sub-samples, including firms in all industries, in science-based industries, and in nonscience-based industries, respectively. First, the results show that the contemporary relationship between R&D and physical investment is positively reciprocal, particularly in science-based industries. That is, current R&D positively affects and is positively affected by current physical investment. Second, it is shown that, in (non-)science-based industries, current R&D (raises) lowers current debt and current physical investment raises current debt; and that current debt raises current physical investment and (raises) reduces R&D. In other words, the evidence supports that debt is a resource to finance both physical investment and R&D in nonscience-based industries, but debt is only a resource to finance physical investment but not R&D in science-based industries.