In this paper, we investigate the real effects of special taxation on banks. We provide evidence that the introduction of a new fiscal levy on banks significantly impairs their performance and has an adverse impact on the real economy through the lending channel. Using micro-level data on lending relationships, we identify the credit supply shock related with a bank tax controlling for loan demand factors. We compute a firm-specific measure of firm exposure to burdened credit institutions. We find a negative impact of the tax shock on investment and output. Our results are important from a policy perspective as they shed light on the economic consequences of double taxation on banks.