We examine the impact of the 2017 U.S. corporate tax cut, enacted through the Tax Cuts and Jobs Act (TCJA), on the timeliness of banks’ loan loss provisions (LLPs). Leveraging the policy threshold that permits small banks with assets under US$500 million to immediately deduct LLPs for tax purposes, we use a difference-in-differences approach to examine how the corporate tax cut affects these banks’ LLP reporting behavior. Using 55,165 bank-quarter observations from 2014 to 2022, we find that the TCJA’s reduction in the corporate tax rate leads to a significant decline in LLP timeliness among small banks. Furthermore, we document that small banks increase the procyclicality of their loans after the tax reform. These findings highlight an unintended consequence of tax policy on banks’ financial reporting and lending practices and contribute to the broader literature on the impacts of corporate tax policies on financial institutions.