This paper examines two potential mechanisms – access to credit and reduction in relational risks – through which social trust can affect R&D investments. Social trust can increase R&D investments by expanding firms' access to external finance with which they can use to fund promising R&D projects. It can also increase R&D investments by reducing relational risks that expose firms to ex-ante and ex-post holdups or expropriation risks. Using industry-level data on R&D investment intensities in 20 OECD countries, I test these mechanisms by evaluating whether more external finance dependent and relational risk vulnerable industries exhibit disproportional higher R&D investment intensities in trust intensive countries. The results indicate that external finance dependent industries and relational risks vulnerable industries experience relatively higher R&D investment intensities in trust-intensive countries. Therefore, the results underline access to external finance and reduction in relational risks as causal pathways linking social trust and R&D investments.
