Finance and R&D Investments - is there a debt overhang effect on R&D investments?

The motivation of this paper is the rather naive approach to debt as a financing source of R&D investment in the empirical investment literature. I focus on long-term relational debt based on its appealing contractual properties and discover a debt overhang effect for the relationship between additional long-term debt and R&D investment. I augment an error correction accelerator-profit specification to include changes in long-term debt as a transitory determinant of R&D investment as has been done with internal finance previously. Firms with previous period debt levels around 0.60 display a positive relationship between additional long-term debt and R&D investment.