Since 2014, states have had the option to expand Medicaid eligibility to adults with incomes below 138 percent of the federal poverty level ($18,754 annually for an individual), with the federal government picking up no less than 90 percent of the cost. States have seen significant budget savings from Medicaid expansion because the federal contribution covers individuals and services that were previously covered with a lower matching rate or with unmatched state funds. Furthermore, the American Rescue Plan Act (ARPA), enacted in early 2021, allows states newly expanding Medicaid to access enhanced federal matching funds for most of their nonexpansion Medicaid populations. Combined with the 90 percent matching rate for expansion adults established under the Affordable Care Act (ACA), ARPA makes the fiscal case for expansion even stronger.
Link: https://www.commonwealthfund.org/blog/2022/medicaid-expansion-mississippi-whats-stake