The Medicaid Bump Act aims to strengthen Medicaid's support for behavioral health services by increasing the federal financial contribution to states. It amends the Social Security Act to provide a 90% federal matching rate for the amount by which a state's expenditures on behavioral health services, encompassing mental health and substance use, exceed their spending from a baseline period ending March 31, 2019. To receive these enhanced funds, states must adhere to specific accountability and maintenance of effort requirements, ensuring the additional federal funding supplements, not supplants , their existing state funds for behavioral health services, based on levels from April 1, 2021. These funds must also be directed towards activities that enhance the capacity, efficiency, and quality of behavioral health service delivery, such as increasing provider payment rates and reducing staff turnover. The Secretary of Health and Human Services is required to issue sub-regulatory guidance within 180 days to define "behavioral health services" for the purposes of this Act. Additionally, the Secretary must submit annual reports to Congress detailing behavioral health services provided under Medicaid, including payment rates, their rationale, and utilization data.