“One Big Beautiful Bill Act” Impacts on the ACA Marketplace Will Be Significant, and Swift

On May 22, the House of Representatives passed the “One Big Beautiful Bill Act,” which will be taken up by the Senate in the coming weeks. The Congressional Budget Office (CBO) that an earlier version of the bill would reduce health insurance coverage for at least 8.6 million Americans and is still evaluating the full impact of the final bill. Considered alongside what the bill did not include—namely the extension of enhanced premium tax credits, suggest nearly 16 million Americans will become uninsured. 

While the impact on Medicaid is significant and has been widely reported, the bill’s effect on the Affordable Care Act’s (ACA’s) Marketplaces has often been left to an “and also” status. The Marketplace as an afterthought is surprising when you consider that three significant market changes are set to impact 24 million individuals, families and thousands of providers across the country in just six short months.

Between 2021 and 2025, enrollment in the ACA Marketplaces doubled from 12 million to over 24 million working individuals and families. This was due not only to incredible gains in affordability but also smart, data-driven work to make signing up for coverage easier for eligible working families with busy lives.

Provisions in the “One Big Beautiful Bill Act” (and the omission of extending the enhanced advanced premium tax credits (APTCs)) would decrease affordability and increase paperwork burden, jeopardizing those significant enrollment gains for Healthcare.gov and the —most notably:

• Eliminating enhanced tax credits. Since 2021, Marketplace coverage has been more affordable because of an enhanced tax credit schedule that decreased the percentage of income enrollees contribute and eliminated the cap on middle-income (those at or over 400% FLP) receiving financial assistance. While previously extended by Congress in 2022, these additional subsidies expire at the end of 2025, and Congress does not appear positioned to extend them. Higher out-of-pocket premiums will be felt immediately by the who receive tax credits, more than 90% of enrollees. Notably, 1.6 million middle-income people will lose all financial assistance. average premiums will increase by around 75%, an increase that will be particularly hard, if not unsustainable, for working low-income families, rural communities, and people who own or work for small businesses that rely on the Marketplaces for insurance. CBO estimates that 4.2 million people will become uninsured without renewal of the enhanced subsidies.  
• Ending “silver loading.” When the federal government stopped reimbursing insurers for cost-sharing reductions (CSRs) in 2017, most states adopted a federally approved strategy called “silver loading” where insurers increased premiums only for silver-tier Marketplace plans to recoup CSR costs. Because APTCs are tied to Silver plan prices, this approach increased the value of tax credits for families not receiving CSRs (middle income families)—making bronze plans cheaper or even free, and more generous gold plans more affordable. The bill’s proposal to refund CSRs would end silver-loading, raising out-of-pocket premiums for the roughly 10 million enrollees who don’t receive CSR benefits today. Some of these individuals will decide coverage is unaffordable and become uninsured— in 2019 suggested 1.2 million, a figure that would be higher today given record high enrollment—or move into less generous plans and become underinsured.
• Making it harder to enroll in less generous coverage. The legislation and CMS reduce consumer opportunity for enrollment in Marketplaces and increases paper verifications and other required actions by individuals working to gain coverage. The legislation also ends industry-standard practice of autoenrollment across insurance years. For example, nearly 11 million people were automatically reenrolled to keep their 2024 coverage in 2025. These steps are touted as fraud reduction, but the effect of unnecessary paperwork burdens is clear—eligible individuals lose coverage.

Increases in the uninsured rates mean providers will experience disruption directly. Today, ACA Marketplace enrollment is greater than Medicaid expansion enrollment. In large, Marketplace plans in non-expansion states—like Texas and Florida—represent a larger portion of insurance coverage for low-income individuals, who would become uninsured or underinsured should plans become more expensive to purchase or use. Overall, more people will become uninsured and will attempt to self-pay or forego needed care. A found that spending on health care services will decrease by $1.03 trillion as a result of the expiration of the enhanced APTC and the legislation over the next ten years, with the impact of the Marketplace provisions taking effect on provider revenue almost immediately.

Finally, insurers will face hard strategic choices as they redesign their insurance offerings, evaluate new operational requirements, face lower enrollment projections and a much less stable market. It’s difficult to imagine how insurers will price such dramatic, simultaneous market changes, but it’s a certainty that premiums will increase to reflect such large uncertainty.

If passed in its current form and enhanced APTC are not extended, the Marketplace will look markedly different. And it’s coming quickly. Absent common-sense prevailing on the coming impacts to affordable insurance coverage for working people nationwide, entities across the health care industry should prepare for significant enrollment declines and position themselves to withstand major market disruption.

Ellen Montz is a nationally respected health care leader bringing deep experience in the Marketplace and private insurance coverage as the former Deputy Administrator and Director at the Center for Consumer Information and Insurance Oversight at CMS from 2021–2025 and in Medicaid as former Chief Deputy and Chief Health Economist at Virginia Medicaid. Kyla Ellis recently served as Deputy Chief of Staff and Senior Advisor to the Administrator at CMS.