Medicaid is a shared financial responsibility between states and the federal government, with the federal government matching state funds based on the Federal Medical Assistance Percentage (FMAP). The Centers for Medicare & Medicaid Services makes these federal funds available to states based on state submissions of expenditures as described in section 1903(d)(1) of the Social Security Act. This issue brief describes the processes used by states to claim federal matching funds and the oversight structure for these financial transfers.