Cash breeds Success: The Role of Financing Constraints in Patent Races

This paper studies the impact of cash constraints on equilibrium winning probabilities in a patent race between an incumbent and an entrant. We develop a model where cash-constrained firms finance their R&D expenditures with an investor who cannot verify their effort. In equilibrium, the incumbent faces better prospects of winning the race the less cash-constrained he is and the more cash-constrained the entrant is. We use NBER evidence from pharmaceutical patents awarded between 1975 and 1999 in the US, patent citations, and COMPUSTAT and fit probabilistic regressions of the predicted equilibrium winning probabilities on measures of the incumbent's and potential entrants' financial wealth. The empirical findings support our theoretical predictions.