Despite historic coverage gains under the Affordable Care Act (ACA), more than 27 million people in the United States remain without insurance coverage.¹ Recent debate over the future of the ACA has led to uncertainty about whether and how ACA coverage will be maintained. The public reports confusion about the future of the law, and outreach to help inform people about coverage options is more limited than in past years. Still, millions of currently uninsured people are eligible for ACA coverage under current law, and given upcoming open enrollment, it is helpful to understand how many people could potentially gain ACA coverage. In addition, the administration has indicated to states that it is open to state Medicaid waiver proposals, which may lead some states that have not yet expanded Medicaid under the ACA to develop Medicaid expansion waivers and further extend coverage. Understanding how many people might be eligible for coverage under the ACA or could be reached with policy changes can inform these policy discussions.

This analysis provides national and state-by-state estimates of eligibility for ACA coverage options among those who remained uninsured. An overview of the methodology underlying the analysis is in the Methods box at the end of the data note and in the Technical Appendices available here.

Background: How Does the ACA Expand Health Coverage?

Under the ACA, Medicaid coverage is extended to nearly all nonelderly adults with incomes at or below 138% of the federal poverty level (FPL) ($28,676 for a family of three in 2018)² in the 34 states (including DC) that had expanded as of June 2018.³ Under rules in place before the ACA, all states extend public coverage to poor and low-income children, with a median income eligibility level of 255% of poverty in 2018.⁴ The ACA also established health insurance marketplaces where individuals can purchase insurance and allows for federal tax credits for such coverage for people with incomes from 100% to 400% FPL ($20,420 to $81,680 for a family of three in 2017).^5,6 Tax credits are generally only available to people who are not eligible for other coverage.

Because the ACA envisioned low-income people receiving coverage through Medicaid, people with incomes below poverty are not eligible for Marketplace subsidies. Thus, in the 17 states that have not implemented the Medicaid expansion, some adults fall into a “coverage gap” of earning too much to qualify for Medicaid but not enough to qualify for premium tax credits. In addition, undocumented immigrants are ineligible for Medicaid coverage and barred from purchasing coverage through a Marketplace. In most cases, lawfully present immigrants are subject to a five-year waiting period before they may enroll in Medicaid, though they can purchase coverage through a Marketplace and may receive tax credits for such coverage.

How Many Uninsured Are Eligible for Assistance under the ACA?

In 2016, 27.5 million nonelderly people lacked health coverage in the U.S. Nationally, we estimate 54% of this population, or 14.8 million people, is eligible for financial assistance to gain coverage through either Medicaid or subsidized Marketplace coverage (Figure 1 and Tables 1 and 2). One quarter are either adults eligible for Medicaid⁷ (4.3 million, or 16%) or children eligible for Medicaid or the Children’s Health Insurance Program (CHIP) (2.7 million, or 10%). Those who are Medicaid eligible include people who were previously eligible as well as those newly eligible under the ACA. More than a quarter (7.8 million, or 28%) of the nonelderly uninsured is eligible for premium tax credits to purchase coverage through the Marketplace.⁸

Figure 1: Eligibility for ACA Coverage Among Nonelderly Uninsured, 2016

More than two million uninsured people (2.2 million) fall into the coverage gap due to their state’s decision not to expand Medicaid. These individuals have incomes below poverty but do not qualify for Medicaid in their state, nor do they qualify for Marketplace tax credits. An additional 14% of the uninsured (3.9 million) are undocumented immigrants who are ineligible for ACA coverage under federal law.

The remainder of the uninsured either has an offer of ESI (3.7 million, or 13%) or has an income above the limit for premium tax credits but could purchase unsubsidized Marketplace coverage (2.9 million, or 10%). We cannot determine from available survey data if the offer of ESI would be considered unaffordable under the law, which would make the individual eligible for a Marketplace premium subsidy.

Patterns of eligibility vary by state (Tables 1 and 2), depending on state decisions about expanding Medicaid, premiums in the exchange, and underlying demographic factors such as poverty rates and access to employer coverage. In states that expanded Medicaid, 37% of the nonelderly uninsured population is eligible for Medicaid, versus just 13% in states that have not expanded Medicaid (Figure 2). No one in Medicaid expansion states falls into a coverage gap; in non-expansion states, nearly one in five (17%) uninsured people falls into the coverage gap, a larger share than the share who are eligible for Medicaid under pathways in place before the ACA. Because adults with incomes from 100% to 138% of poverty in non-expansion states can receive tax credits for Marketplace coverage, a larger share of the uninsured population in those states is eligible for Marketplace tax credits than in expansion states (34% versus 23%).

Figure 2: Eligibility for ACA Coverage Among Nonelderly Uninsured by State Medicaid Expansion Status, 2016

Discussion

Going without health insurance has adverse implications for people’s health and financial well-being and has negative consequences for providers and the health system. Survey results indicate that a very small share of the uninsured population—about 2% in 2016—say that the reason they go without insurance is because they don’t want coverage.⁹ Rather, people remain uninsured due to limits on eligibility, ongoing concerns about cost, or lack of awareness of affordable options.

The ACA extended health insurance to millions of previously uninsured Americans and, despite ongoing debate about the future of the ACA, has the potential to reach more uninsured people. We estimate that more than half of the uninsured population are eligible for Medicaid or subsidized Marketplace coverage. For these individuals, outreach and education about coverage and financial assistance will be important to continuing coverage gains that were seen in the early years of full ACA implementation. Data from other sources indicate that misperceptions about cost, lack of awareness of financial assistance, and confusion about eligibility rules were initial barriers to gaining coverage for some eligible uninsured.^10,11,12 Others report that they found coverage to be too expensive, even with the availability of financial assistance. Recent policy changes and debate, such as cuts to funding for ACA enrollment assistance, uncertainty about federal payments for cost-sharing reductions, and debate over the future of Medicaid coverage, may exacerbate these challenges and make continued coverage gains difficult.

Nearly one in ten of the remaining uninsured population is outside the reach of the ACA due to their state’s decision not to expand Medicaid. People in the coverage gap would be eligible for Medicaid should their state opt to expand Medicaid but are otherwise likely to remain uninsured, as they have limited incomes, are unlikely to have an affordable offer of coverage from an employer, and do not have access to affordable coverage options under the ACA. While there is no deadline for states to expand Medicaid under the ACA, several non-expansion states have reported that consideration of the Medicaid expansion is on hold due to uncertainty about the future of the Medicaid expansion option.

In addition, 14 percent of the uninsured population is ineligible for coverage due to their immigration status. Most uninsured undocumented immigrants will likely remain without coverage, though there are some state or locally-funded programs that provide coverage or assistance to immigrants regardless of immigration status.¹³ Recent actions by the Administration to increase immigration enforcement activities could deter people from enrolling in these programs. They also have spillover effects of deterring eligible immigrants in mixed status families from enrolling in coverage.

Approximately a quarter of the uninsured population is not eligible for any assistance under the ACA because they have access to employer coverage that may be considered affordable or have incomes too high to qualify for Medicaid or Marketplace subsidies. Some of these people may face a financial penalty under the ACA’s so-called “individual mandate.” However, notable shares of uninsured adults are either unaware that the mandate is in effect or are misinformed about its scale, and a minority of those who have purchased ACA coverage say the mandate was a major motivating factor.¹⁴

In the months leading to open enrollment for 2019 Marketplace coverage, there are substantial opportunities to increase coverage by reaching those who are eligible for help under the ACA. However, given confusion and misinformation about the ACA, many may be difficult to reach without targeted and effective outreach to explain coverage options and assist with enrollment.