Medicare Advantage Overpayments and Rising Part B Premiums

A new congressional report is drawing renewed attention to a long-standing issue within Medicare financing: overpayments to Medicare Advantage plans. According to a brief released by the Senate Joint Economic Committee, these excess payments have quietly increased Medicare Part B premiums for all beneficiaries—regardless of whether they are enrolled in Medicare Advantage or Original Medicare.

Over the past decade alone, the report estimates that these overpayments have added roughly $82 billion to Part B premiums. While Medicare Advantage enrollment continues to grow and many beneficiaries appreciate the additional benefits these plans often advertise, the financing structure behind the program has implications that reach far beyond the individuals who enroll in it.

The Joint Economic Committee report highlights a simple but important reality: when Medicare Advantage plans are paid more than it would cost the government to cover the same beneficiaries under Original Medicare, those higher costs feed directly into the overall Part B spending calculation. Because Part B premiums are designed to cover approximately twenty-five percent of total program costs, higher spending automatically results in higher premiums for everyone in the program.

In 2025, the report estimates that Medicare Advantage overpayments increased the annual Part B premium by approximately $212 per beneficiary. Across the Medicare population, that amounts to roughly $13.4 billion in additional premiums for the year. Notably, a substantial portion of this burden falls on individuals who are not enrolled in Medicare Advantage at all. Beneficiaries who remain in Original Medicare—who generally do not have access to the supplemental benefits offered by many Medicare Advantage plans—shouldered about $6 billion of the added premium costs.

The financial impact is not limited to beneficiaries. The report also notes that taxpayers share in the cost. While Medicare enrollees ultimately bear most of the increased premiums, the remainder of the burden falls on federal and state governments through transfers into the Medicare Part B trust fund.

At the center of the issue is the original promise of Medicare Advantage. The program was designed to allow private insurers to deliver Medicare benefits more efficiently than the traditional fee-for-service model. Policymakers believed that private plans would innovate, manage care more effectively, and ultimately reduce the overall cost of Medicare.

According to the Joint Economic Committee’s analysis, that promise has yet to materialize. Data from the non-partisan Medicare Payment Advisory Commission indicates that Medicare Advantage plans cost the program approximately seventeen to twenty percent more than Original Medicare on average in 2025. That translates to tens of billions of dollars in additional payments each year.

The report defines these overpayments as the difference between what Medicare pays Medicare Advantage plans and what it would have spent covering the same beneficiaries under the traditional program. While the mechanics of the payment system are complex and involve risk adjustments, benchmarks, and quality incentives, the end result is relatively straightforward: Medicare Advantage plans are receiving higher payments on average than the traditional program for comparable beneficiaries.

This cost difference flows directly into the financing structure of Medicare Part B. The Supplementary Medical Insurance Trust Fund, which finances Part B, relies on a combination of beneficiary premiums and transfers from the federal government’s general fund. Each year, premiums are calibrated to cover roughly one quarter of the program’s expected spending. When spending increases, premiums increase as well.

Importantly, the Part B premium does not vary depending on whether a beneficiary receives their coverage through Original Medicare or through Medicare Advantage. In other words, even beneficiaries who never enroll in a Medicare Advantage plan still pay a share of the higher costs generated by those plans.

The impact becomes even more tangible when viewed through the lens of Social Security benefits. Nearly seventy percent of Medicare beneficiaries have their Part B premiums automatically deducted from their Social Security checks. As a result, any increase in the premium directly reduces the amount of income those retirees receive each month.

From a beneficiary’s perspective, this means that rising Medicare costs can quietly erode the purchasing power of their Social Security benefit. When premiums increase, retirees effectively see a reduction in their net monthly income—even if their gross benefit remains unchanged.

Looking forward, the report suggests that the problem may grow more significant if policy remains unchanged. Current projections show that average annual Part B premiums could rise dramatically over the next decade, increasing from roughly $2,400 per year in 2025 to approximately $5,000 by 2035. If Medicare Advantage plans continue to be paid at levels substantially higher than Original Medicare, the additional premium burden attributable to overpayments could more than double over the same period.

These projections come at a time when many retirees are already facing financial pressure. A large share of Medicare beneficiaries live on relatively modest incomes, and many rely heavily on Social Security as their primary source of retirement income. According to the data cited in the report, half of Medicare beneficiaries live on annual incomes of $43,200 or less, and a quarter have less than $18,950 in savings.

For households in that position, rising healthcare costs can create difficult tradeoffs between medical care and other essential expenses. When premiums, deductibles, and cost-sharing all rise simultaneously, the cumulative effect can place significant strain on fixed retirement budgets.

The Joint Economic Committee report concludes that policymakers have the ability to address this issue through reforms that align Medicare Advantage payments more closely with the cost of providing the same care under Original Medicare. According to the analysis, gradually achieving payment parity could save the average senior roughly $2,600 in premiums over the next decade.

From the perspective of the National Social Security Advisors, the connection between Medicare policy and Social Security income is especially important. Advisors who help clients plan for retirement often focus on claiming strategies, longevity planning, and income replacement. Yet healthcare costs—particularly Medicare premiums—play an equally critical role in determining how much income retirees actually retain.

When Part B premiums rise, the reduction is felt immediately through lower Social Security deposits. This dynamic underscores the importance of viewing retirement planning holistically. Social Security benefits do not exist in isolation; they interact with Medicare premiums, tax policy, and healthcare inflation in ways that can materially affect retirement outcomes.

For financial advisors and retirement professionals, the key takeaway is that Medicare policy changes can have direct consequences for the net income their clients receive. Understanding these dynamics allows advisors to better explain why Social Security checks sometimes increase more slowly than expected and why healthcare costs remain a central factor in retirement planning.

The broader policy debate surrounding Medicare Advantage will likely continue, as the program now covers more than half of all Medicare beneficiaries and remains a major component of the Medicare landscape. Many beneficiaries value the convenience and additional benefits offered by Medicare Advantage plans, and the program will undoubtedly remain an important option for retirees.

At the same time, the financing structure of Medicare must balance those benefits with long-term sustainability and fairness for all participants. When policy choices lead to higher program costs that are distributed across the entire Medicare population, those consequences deserve careful attention.

For retirees and advisors alike, the lesson is clear: Medicare premiums are not simply administrative fees deducted from Social Security benefits. They reflect broader policy decisions about how the healthcare system is financed and how costs are distributed among beneficiaries and taxpayers.

As policymakers evaluate potential reforms in the years ahead, the relationship between Medicare spending and Social Security income will remain a critical issue for millions of American retirees. Understanding that relationship—and helping clients plan for it—remains an essential part of responsible retirement planning.