We investigate the effect of individual banks’ affected by the recent financial crisis of 2008/2009 on the innovation activities of their business customers. Firms associated with a bank that relies more on the interbank market are more likely to be exposed to a credit supply shock during the financial crisis and therefore face external financing constraints. Exploiting both the extensive and the intensive margin, our difference-in-differences results imply that those firms which have a business relation to a bank with higher interbank market reliance reduce their innovation activities during the financial crisis to a higher degree than other firms. Tests for additional expenditures reveal that marketing expenditures show a lower or even no sensitivity to bank financing during the financial crisis.