The Congressional Budget Office (CBO) recently relation projections of US health insurance levels between 2024 and 2034. In the Hale et al. (2024) study, CBO estimates that:

…92.3 percent of the US population, or 316 million people, have coverage in 2024, and 7.7 percent, or 26 million, are uninsured. The uninsured share of the population will rise over the course of the next decade, before settling at 8.9 percent in 2034, largely as a result of the end of COVID-19 pandemic–related Medicaid policies, the expiration of enhanced subsidies available through the Affordable Care Act health insurance Marketplaces, and a surge in immigration that began in 2022. The largest increase in the uninsured population will be among adults ages 19–44. Employment-based coverage will be the predominant source of health insurance, and as the population ages, Medicare enrollment will grow significantly. After greater-than-expected enrollment in 2023, Marketplace enrollment is projected to reach an all-time high of twenty-three million people in 2025.

https://www.healthaffairs.org/doi/10.1377/hlthaff.2024.00460

CBO estimates that Medicare enrollment (in Parts A and B) will rise from 61m in 2024 to 74m in 2034. This is not surprising with an aging population. Perhaps more surprising is that CBO projects Medicare Advantage enrollment will rise from just over half of beneficiaries in 2024 to nearly two-thirds of beneficiaries in 2034.

CBO estimates for health insurance levels for the civilian noninstitutionalized population aged <65 years are based on the CBO’s Health Insurance Simulation Model (HISIM2), a structural expected utility model. The details behind the HISIM2 model are explained in Hanson et al. (2023).

You can read the full study here, and the full baseline projections here.