Budget legislation signed by President Trump in July 2025, combined with Congress’s decision not to extend “enhanced” premium subsidies in the Affordable Care Act (ACA) marketplaces, is predicted to increase the number of uninsured Americans by 16 million by the year 2034, according to the Congressional Budget Office (CBO) [1,2]. In 2024, it was estimated that there were 27.2 million uninsured Americans, well below the 49 million in 2010, prior to the implementation of the ACA [3, 4].
The new legislation, named the “One Big Beautiful Bill” (OBBB) Act, was intended to extend Trump’s tax legislation from his first term, which otherwise was about to expire. This required generating trillions of dollars in savings from government programs. Below, we discuss the major reasons that the number of uninsured Americans is expected to rise so much.
Medicaid work verification requirements
The CBO estimates the largest share of Medicaid savings ($326 billion over 10 years) to come from changing Medicaid expansion eligibility by implementing work requirements [5]. Prior to the OBBB, federal law prohibited linking Medicaid eligibility to working or looking for work. However, states could obtain waivers from the federal government to implement work requirements. These demonstration waivers were approved in several states during the first Trump administration, though later rescinded by the Biden administration. Georgia is currently the only state with an approved work requirement waiver, though more than a dozen have applied for waivers to implement them [6].
Under the OBBB, working-age individuals enrolled in or applying for Medicaid expansion in any state would be required to verify they are working or participating in qualifying activities (e.g., looking for work, job training) at least 80 hours per month. Parents of dependent children age 13 or younger or individuals who are medically frail are exempted from work requirements [7] (effective 31 December 2026, although the Secretary of Health and Human Services can extend this deadline by two years for states acting in good faith to implement the requirements).
Already, 64% of working-age individuals enrolled in Medicaid, who are not covered by disability insurance, report working part or full time [8]. Evidence from Arkansas’s attempt to implement a work requirement waiver in 2018 resulted in 25% (18,000) of those eligible for the work requirement losing Medicaid coverage, an increase in the uninsurance rate in the state, with no change in unemployment rates. Many people lost Medicaid because they had trouble reporting and verifying their work or other qualifying activities. Of the 13 states that had approved or in-progress demonstrations to implement work requirements during the first Trump administration, Michigan Medicaid was estimated to lose 100,000 otherwise eligible individuals due to work requirements, prior to a judge blocking implementation [10]. The CBO estimates that 18.5 million people will be subject to work requirements each year, and in 10 years, 5.2 million fewer adults will be enrolled in Medicaid. Few of these are expected to find other coverage, given provisions in the OBBB that those who are not eligible for Medicaid due to work requirements are also ineligible for marketplace subsidies, thus increasing the number of those without insurance by a further 4.8 million [11].
In addition to work requirements, the OBBB requires states to redetermine eligibility at least every 6 months instead of annually (effective 2026, resulting in a budget reduction of $63 billion over 10 years [12]). Further, retroactive coverage is limited to 1 month for expansion enrollees, a decrease from 3 months of retroactive coverage in federal law prior to the OBBB.
Other Medicaid changes
Changes to financing Medicaid expansion enacted through the OBBB include the elimination of temporary incentives (+5% to the federal matching rate for 2 years) for the 12 states that have not already expanded Medicaid, essentially disincentivizing those who have not expanded already to now do so (effective 1 January 2026) [13]. The OBBB will also limit federal matching for providing emergency services to individuals who would otherwise be eligible for Medicaid expansion but for their immigration status (effective 1 October 2026). Regarding premiums and out-of-pocket payments, the OBBB eliminates optional enrollment fees and premiums but requires states to charge up to $35 in cost-sharing for the expansion population. However, many services (e.g., primary care, mental health, substance use services) and providers (e.g., rural health clinics, federally qualified health centres) are exempt from cost sharing (effective 1 October 2028 [7] and expected to reduce the federal budget by $7 billion over 10 years).
Provider taxes that currently help finance Medicaid in many states will also be affected by the OBBB. Specifically, states that have expanded Medicaid will have the provider tax limit, referred to as the safe harbour limit, reduced from 6% to 3.5%. This policy is expected to decrease provider tax revenue for the state Medicaid program in 22 expansion states, mostly through taxes to hospitals on their net patient revenues [14]. These changes to provider taxes will begin in 2028 with 0.5% reductions occurring in expansion states until the 3.5% limit is reached and are expected to reduce federal Medicaid spending by $191 billion over 10 years [12]. In addition to financing changes specific to Medicaid expansion, more broadly, the OBBB includes new limits to payments that state Medicaid programs can make to hospitals and nursing facilities via Medicaid managed care programs, affecting provider payments in approximately 30 states [14] (effective upon enactment, expected to reduce the budget by $149 billion over 10 years).
Changes to marketplaces
While the original premium subsidies that went into effect in 2014 resulted in millions of Americans obtaining health insurance coverage, many were still unable to afford the premiums. One reason is that they were available only to those whose incomes were no more than four times the federal poverty level (currently, $15,650 for an individual and $32,150 for a family of four). Another consideration was that premiums could vary by a factor of three depending on age, resulting in older prospective purchasers frequently facing premiums that represented a significant portion of their income. In 2021, legislation passed under the Biden Administration expanded premium subsidies so that no one would pay more than 8.5% of their income for a so-called “benchmark plan.” Coverage became more affordable, particularly for people close to retirement. These enhanced subsidies will end after 2025, as Congress did not extend them under the OBBB. As a result, on average, policyholders will face more than a 75% increase in their out-of-pocket premiums [15, 2].
As noted, CBO predicts an increase of 16 million uninsured persons by 2034. An estimated 4.2 million will be the result of the expiration of the enhanced premiums. Another 0.9 million will be due to other changes made to the marketplaces. One of the most significant ones is the shortening of the open enrollment period from 2.5 months to 1.5 months.
Impacts on access to healthcare and health
OBBB provisions will lower access to healthcare in several ways. The drop in insured people due to Medicaid and ACA cuts will reduce patients’ ability to obtain healthcare. In addition, reductions in the number of insured will lead to financial distress for healthcare providers such as physicians and hospitals. This will result in a reduction in services and the closing of hospitals, further reducing access to care for many Americans [16]. Rural clinics and hospitals, which see a higher proportion of Medicaid patients, will be heavily affected.
Access to care will also be affected by limitations on the amount of federal loan money medical students can obtain [17], making it more difficult for students to finance medical school. This may discourage students from entering medical school, thereby exacerbating an existing physician shortage. Rural areas will be especially hard hit as they will need to pay physicians more for them to pay off their medical school debts.
The health impacts of the bill have been estimated. The estimates are based on drafts of the bill by the House or Senate and vary based on the estimated loss of insurance and services arising from the bills. Gaffney and colleagues estimate that, due to the loss of Medicaid and ACA insurance, the proposed House version of the bill would increase deaths by between 8,200 and 24,600 annually, with a mid-range of 16,642 [18]. The Leonard Davis Institute (LDI) at the University of Pennsylvania and the Center for Disease Modeling and Analysis at Yale University predict a total of 42,500 additional deaths annually from the bill’s changes: 11,300 due to people losing coverage from loss of Medicaid or ACA; 18,200 from low-income Medicare beneficiaries losing Medicaid prescription drug subsidies, and 13,000 from low staffing in nursing homes [19]. The LDI estimates that the impact of the loss of access to treatment for opioid use disorder will result in a doubling of the overdose rate, increasing the rate of fatal overdoses by approximately 1,000 each year [20]. The LDI also estimates that the projected loss of Supplemental Nutrition Assistance Program (SNAP) benefits by 3.2 million Americans will result in 93,000 premature deaths by 2029.
As of yet, there are no estimates of the impacts on health inequities, but it is evident that the insurance losses from this bill will be felt by lower-income and disadvantaged persons who rely on Medicaid and the ACA marketplace. The same can be said of the reductions in SNAP.