Medicaid expansion

What is Medicaid expansion?

A provision in the Affordable Care Act (ACA) called for the expansion of Medicaid eligibility to cover more low-income Americans. Under the expansion guidelines, Medicaid eligibility is extended to adults under age 65 with incomes up to 138% of the federal poverty level/FPL (133% plus a 5% income disregard).

Pre-ACA, Medicaid was generally never available to non-disabled adults under age 65 unless they had minor children. And even then, the income caps to qualify as a parent/caretaker were very low. By expanding Medicaid, the ACA created a viable pathway to coverage for millions of low-income adults.

Why are there some states that haven't implemented Medicaid expansion?

The ACA called for Medicaid expansion nationwide. But in June 2012, the Supreme Court ruled that states could not be forced to expand their Medicaid programs, so it was left to each state to determine whether to participate or not.

When Medicaid expansion took effect in 2014, it was only available in 26 states and DC. In the ensuing years, there has been a slow but steady increase in the number of states implementing Medicaid expansion. As of early 2025, Medicaid had been expanded in 40 states and the District of Columbia (see list below). Oklahoma, Missouri, South Dakota, and North Carolina are the most recent states to have expanded Medicaid, all doing so between 2021 and 2023.

Wisconsin is not counted among the Medicaid expansion states, but the rules are different there. Wisconsin has implemented what essentially amounts to a partial expansion of Medicaid, and has no coverage gap (described below) because Medicaid is available to low-income adults with income below the poverty level.

But because Wisconsin has not fully expanded Medicaid as called for in the ACA (meaning, Medicaid is not available in Wisconsin to adults with income between 100% and 138% of the poverty level), the state does not receive the enhanced federal Medicaid funding that it would receive if it fully expanded Medicaid.

Georgia partially expanded Medicaid in the summer of 2023, using an approach similar to Wisconsin's (ie, it still counts as a non-expansion state), and also incorporating a work requirement. Like Wisconsin, Georgia is not receiving the enhanced federal funding that would be available if the state were to fully expand Medicaid. And enrollment in Georgia's partial Medicaid expansion has been quite low, with only about 6,500 people enrolled as of early 2025¹ (versus more than 450,000 who would be eligible if the state adopted full Medicaid expansion without a work requirement²).

How is Medicaid expansion funded?

The federal government is financing most of the cost of expanding Medicaid, and a small portion is being paid by participating states. The costs for enrollees who are newly eligible under the expanded guidelines were covered 100% by the federal government until the end of 2016. The states then gradually started paying a portion of the cost, reaching 10% by 2020.

Assuming the ACA remains intact and isn't changed by future legislation, the funding will remain at the 90/10 split going forward, with the federal government always paying 90% of the cost of covering the population that became newly eligible due to the expansion of Medicaid. (As described below, some states have rules in place that would automatically end Medicaid expansion if the federal match rate were to be reduced.)

The states that refuse to expand Medicaid only receive their normal federal Medicaid funding, rather than the enhanced 90% funding that they would receive to cover the newly eligible population if they were to expand coverage (in the Medicaid expansion states, the normal federal funding still applies for the populations that were already eligible pre-expansion, including children, pregnant women, and low-income parent/caretaker relatives, as well as elderly, blind, and disabled enrollees whose eligibility is subject to both income and asset limits).

As noted above, the federal government does not provide this funding unless a state fully expands Medicaid. So Wisconsin and Georgia continue to receive their normal federal match for Medicaid funding, and Utah was unable to secure Medicaid expansion funding until Medicaid was fully expanded (Utah initially implemented a partial expansion of Medicaid, but did not receive enhanced federal funding for it).

How many people are enrolled in coverage due to Medicaid expansion?

As of June 2024, Medicaid expansion enrollment stood at about 20.9 million people.³

It had been even higher, at about 24.8 million people in May 2023.⁴ But after a three-year pandemic-related pause, Medicaid eligibility redeterminations and disenrollment resumed in 2023, in a process referred to as "unwinding." This resulted in a significant drop in total Medicaid enrollment nationwide, including a reduction of about 4 million Medicaid expansion enrollees.

What is the Medicaid coverage gap?

In the states that have not expanded Medicaid, there's a coverage gap that leaves almost 1.5 million people ineligible for any sort of affordable coverage. These people are not eligible for premium subsidies in the Marketplace because their income is under the poverty level. But they are also ineligible for Medicaid because their states have refused to implement Medicaid expansion.

According to US Census data, the percentage of people below the poverty level who are uninsured is more than twice as high in states that haven't expanded Medicaid, compared with states that have. To be clear, this is due to the decisions that their states have made, rather than a flaw in the ACA itself. The states could opt to accept federal funding to expand Medicaid at any time, thus closing the coverage gap.

Five states — Texas, Florida, Georgia, and Alabama — account for the lion's share of the coverage gap population, and they are among the 10 states where Medicaid expansion is still a contentious issue and the legislature and/or governor are still strongly opposed to accepting federal funding to expand Medicaid.

For people in the coverage gap who received unemployment compensation for at least one week in 2021, the American Rescue Plan provided eligibility for premium subsidies. But this was a temporary provision for 2021.

The Build Back Better Act would have provided federal subsidies for four years to people in the coverage gap, allowing them to purchase premium-free coverage with enhanced benefits that leave them with very little out-of-pocket costs. That legislation passed the House in the fall of 2021, but stalled in the Senate due to objections from all GOP Senators as well as two Democrats.

There were ongoing negotiations in 2022 about federal funding to close the Medicaid coverage gap. But ultimately, the Inflation Reduction Act was enacted in 2022 without any provision to close the Medicaid coverage gap (it did, however, extend some of the American Rescue Plan subsidy enhancements, and also provided significant benefit improvements for people with Medicare drug coverage).

Which states have expanded Medicaid?

As of early 2025, Medicaid has been expanded in 40 states and Washington, D.C.

• Alaska
• Arizona
• Arkansas
• California
• Colorado
• Connecticut (for parents, eligibility extends to 160% FPL)
• Delaware
• Hawaii
• Idaho
• Illinois
• Indiana
• Iowa
• Kentucky
• Louisiana
• Maine
• Maryland
• Massachusetts
• Michigan
• Minnesota
• Missouri
• Montana
• Nebraska
• Nevada
• New Hampshire
• New Jersey
• New Mexico
• New York
• North Carolina
• North Dakota
• Ohio
• Oklahoma
• Oregon
• Pennsylvania
• Rhode Island
• South Dakota
• Utah
• Vermont
• Virginia
• Washington
• Washington, D.C. (eligibility extends to 215% FPL)
• West Virginia
  

Which states have refused to expand Medicaid?

As of early 2025, the following states have not yet accepted federal funding to expand Medicaid:

• Alabama
• Florida
• Georgia (partial expansion took effect in mid-2023, with a work requirement)
• Kansas
• Mississippi
• South Carolina
• Tennessee (no coverage gap for parents of minor children)
• Texas
• Wisconsin (no coverage gap)
• Wyoming
  

Which states would automatically end Medicaid expansion if the federal funding rate is reduced?

Under the ACA, the federal government pays 90% of the cost of covering the Medicaid expansion population, while states pay 10% of the cost. But several states have laws in place that would automatically terminate Medicaid expansion in the state if that federal matching percentage were to ever drop below 90%.⁶

Learn more about the 12 states whose Medicaid trigger laws would quickly end or scale back Medicaid expansion if the share of federal funding for Medicaid expansion drops.