To estimate the budgetary effects, CBO and JCT projected how the legislation would change the number of people who obtain federally subsidized health insurance through Medicaid, the nongroup market, and the employment-based market, as well as many other factors.

CBO and JCT estimate that, in 2018, 14 million more people would be uninsured under the legislation than under current law. Most of that increase would stem from repealing the penalties associated with the individual mandate. Some of those people would choose not to have insurance because they chose to be covered by insurance under current law only to avoid paying the penalties, and some people would forgo insurance in response to higher premiums.

Later, following additional changes to subsidies for insurance purchased in the nongroup market and to the Medicaid program, the increase in the number of uninsured people relative to the number under current law would rise to 21 million in 2020 and then to 24 million in 2026. The reductions in insurance coverage between 2018 and 2026 would stem in large part from changes in Medicaid enrollment—because some states would discontinue their expansion of eligibility, some states that would have expanded eligibility in the future would choose not to do so, and per-enrollee spending in the program would be capped. In 2026, an estimated 52 million people would be uninsured, compared with 28 million who would lack insurance that year under current law.