Using the staggered deregulation of the U.S. banking industry as a series of exogenous shocks, I study the effect of the credit supply on the speed of capital structure adjustment. I find robust evidence that interstate and intrastate banking deregulation are positively associated with leverage adjustments. Specifically, the speeds of adjustment to target leverage are faster in the postderegulation periods. I also find that the positive effect is driven by firms that are financially constrained, are financially dependent on banks, and have less access to the public debt market and by deregulated banks' ability to geographically diversify the credit risk.