By integrating staggered interstate banking deregulation into a gravity model following Goetz, Laeven, and Levine (2013), (2016), we construct a time-varying, bank-specific instrument for geographic diversification and investigate its causal effect on corporate innovation via the lending channel. We find that bank geographic diversification spurs corporate innovation and enhances the economic value of innovation. We identify relaxing debt covenants and alleviating borrowers’ financial constraints as the two underlying mechanisms explaining the documented effects. Moreover, by offering lenient covenants, geographically diversified banks provide greater financial and operational flexibility to borrowing firms, enabling them to engage in future mergers and acquisitions.