H.R. 4089 would require the Department of Homeland Security (DHS) to develop and disseminate best practices for vehicle rental companies and dealers to report suspicious behavior when a rental vehicle is sold. DHS would be required to consult with state, local, and tribal governments and industry stakeholders and report to the Congress on implementation of the best practices after one year. Based on the cost of similar activities, CBO estimates that implementing the bill would cost less than $500,000 over the 2021-2026 period; such spending would be subject to the availability of appropriated funds.