The Federal Medical Assistance Percentages (FMAPs) are used in determining the amount of Federal matching funds for State expenditures for assistance payments for certain social services, and State medical and medical insurance expenditures. The Social Security Act requires the Secretary of Health and Human Services to calculate and publish the FMAPs each year.
The “Federal Medical Assistance Percentages” are for Medicaid. Section 1905(b) of the Act specifies the formula for calculating Federal Medical Assistance Percentages.
Further reading –
https://www.medicaid.gov/medicaid/financing-and-reimbursement/