• Part A is financed primarily through a 2.9 percent tax on earnings paid by employers and employees (1.45 percent each) (accounting for 88 percent of Part A revenue). Higher-income taxpayers (more than $200,000/individual and $250,000/couple) pay a higher payroll tax on earnings (2.35 percent).
• Part B is financed through general revenues (72 percent), beneficiary premiums (26 percent), and interest and other sources (2 percent). Beneficiaries with annual incomes over $85,000/individual or $170,000/couple pay a higher, income-related Part B premium reflecting a larger share of total Part B spending, ranging from 35 percent to 85 percent.
• Part D is financed by general revenues (71 percent), beneficiary premiums (17 percent), and state payments for beneficiaries dually eligible for Medicare and Medicaid (12 percent). Higher-income enrollees pay a larger share of the cost of Part D coverage, as they do for Part B.
• The Medicare Advantage program (Part C) is not separately financed. Medicare Advantage plans, such as HMOs and PPOs, cover Part A, Part B, and (typically) Part D benefits. Beneficiaries enrolled in Medicare Advantage plans pay the Part B premium, and may pay an additional premium if required by their plan; about half of Medicare Advantage enrollees pay no additional premium.

Assessing Medicare’s Financial Condition

Medicare’s financial condition can be assessed in different ways, including comparing various measures of Medicare spending—overall or per capita—to other spending measures, such as Medicare spending as a share of the federal budget or as a share of GDP, as discussed above, and estimating the solvency of the Medicare Hospital Insurance (Part A) trust fund.

Solvency of the Medicare Hospital Insurance Trust Fund

The solvency of the Medicare Hospital Insurance trust fund, out of which Part A benefits are paid, is one way of measuring Medicare’s financial status, though because it only focuses on the status of Part A, it does not present a complete picture of total program spending. The solvency of Medicare in this context is measured by the level of assets in the Part A trust fund. In years when annual income to the trust fund exceeds benefits spending, the asset level increases, and when annual spending exceeds income, the asset level decreases. When spending exceeds income and the assets are fully depleted, Medicare will not have sufficient funds to pay all Part A benefits.

Each year, Medicare’s actuaries provide an estimate of the year when the asset level is projected to be fully depleted. In the 2019 Medicare Trustees report, the actuaries projected that the Part A trust fund will be depleted in 2026, the same year as their 2018 projection and three years earlier than their 2017 projection (Figure 8). The actuaries estimate that Medicare will be able to cover 89 percent of Part A costs from payroll tax revenue in 2026.

In the 2018 and 2019 Medicare Trustees reports, the actuaries attributed the earlier depletion date to several factors, including legislative changes enacted since the 2017 report that will reduce revenues to the Part A trust fund and increase Part A spending:

• lower-than-expected revenues from payroll taxes in 2017 and 2018 due to lowered wages and lower levels of projected GDP;
• lower revenue projections from taxation of Social Security benefits (which provided 8 percent of Part A revenues in 2018) as a result of the tax cut legislation enacted in December 2017;
• higher-than-expected spending for Part A benefits and higher projected provider payment updates;
• higher spending projections due repeal of the ACA’s individual mandate, which is expected to increase the number of people without health insurance, which will result in an increase in Medicare’s disproportionate share hospital (DSH) payments for uninsured patients; and
• higher spending projections due to repeal of the Independent Payment Advisory Board, which would have helped to control Medicare spending if the growth rate exceeded certain target levels.

In general, Part A trust fund solvency is also affected by the level of growth in the economy, which affects Medicare’s revenue from payroll tax contributions, by overall health care spending trends, and by demographic trends—of note, an increasing number of beneficiaries, especially between 2010 and 2030 when the baby boom generation reaches Medicare eligibility age, and a declining ratio of workers per beneficiary making payroll tax contributions.

Part B and Part D do not have financing challenges similar to Part A, because both are funded by beneficiary premiums and general revenues that are set annually to match expected outlays. Expected future increases in spending under Part B and Part D, however, will require increases in general revenue funding and higher premiums paid by beneficiaries.

The Future Outlook

Although Medicare spending is on a slower upward trajectory now than in past decades, total and per capita annual growth rates are trending higher than their historically low levels of the past few years. The aging of the population, growth in Medicare enrollment due to the baby boom generation reaching the age of eligibility, and increases in per capita health care costs are leading to growth in overall Medicare spending. At the same time, recent legislative changes, including repeal of the ACA’s individual mandate and repealing IPAB, have worsened the short-term outlook for the Medicare Part A trust fund and have led to projections of higher Medicare spending in the future.

A number of changes to Medicare have been proposed in the past to address the fiscal challenges posed by the aging of the population and rising health care costs. Lately, policymakers have been focused more narrowly on policy options to control Medicare prescription drug spending, rather than on broader proposals to reduce the growth in Medicare spending. And there has been little discussion of revenue options that could be considered to help finance care for Medicare’s growing and aging population, including raising the Medicare payroll tax or increasing other existing taxes. Meanwhile, Medicare has featured prominently in the 2020 presidential campaign, with proposals from some Democratic candidates to expand on it as part of a Medicare-for-all plan, and ideas from others to allow people to buy into it.

The prospects for proposals that would affect Medicare’s financial outlook are unknown, but they will require careful deliberation over the effects on not only the program’s finances but also its growing number of beneficiaries.