The law, which Congress passed with bipartisan support, eases rules on all but the largest institutions.
Proponents argue the measures will help community lenders, while opponents contend it went too far to help mid-sized and regional firms.
President Donald Trump signed the biggest rollback of bank regulations since the global financial crisis into law Thursday.
The measure designed to ease rules on all but the largest banks passed both chambers of Congress with bipartisan support. Backers say the legislation will lift burdens unnecessarily put on small and medium-sized lenders by the Dodd-Frank financial reform act and boost economic growth.
Opponents, however, have argued the changes could open taxpayers to more liability if the financial system collapses or increase the chances of discrimination in mortgage lending.