Medicare Advantage Overpayments: What Billions in Excess Costs Mean for You

If you're enrolled in Original Medicare — or even if you're weighing whether to switch to a Medicare Advantage plan — there's a financial story unfolding in Washington that directly affects your premiums, your program's long-term stability, and the value of your coverage. Federal investigators and independent health policy researchers have documented what they describe as a systemic pattern of overpayments to Medicare Advantage insurers, potentially totaling tens of billions of dollars each year. Understanding how this works, and what it means for you, requires a quick look under the hood of how Medicare Advantage is funded.

Medicare Advantage plans — the private insurance alternative to Original Medicare — are paid a fixed monthly amount per enrollee by the federal government. That payment is supposed to reflect how sick or healthy each enrollee is, using a system called risk adjustment. The sicker the patient on paper, the higher the monthly payment the insurer receives from Medicare. This system was designed to be fair: plans that attract sicker patients should get more money to cover their higher costs. But investigators, including the Department of Health and Human Services Office of Inspector General (OIG) and the Government Accountability Office (GAO), have found that many insurers have gamed this system by systematically adding diagnoses to patient records — a practice called 'upcoding' — to make their enrollees appear sicker than they actually are, thereby collecting inflated payments.

The scale of the alleged overpayments is staggering. The Medicare Payment Advisory Commission (MedPAC), which advises Congress on Medicare spending, has estimated that Medicare Advantage plans are overpaid by roughly 6% compared to what the same patients would cost under Original Medicare — a gap that has translated to tens of billions of dollars annually. In 2024, Medicare Advantage enrollment surpassed 33 million people, representing more than half of all Medicare beneficiaries. At that scale, even a modest per-enrollee overpayment compounds into an enormous drain on the Medicare Trust Fund. Some analyses have put cumulative overpayments over the past decade well into the hundreds of billions of dollars.

How does upcoding actually work in practice? Insurers have used several methods. Some send nurses or health workers to enrollees' homes for 'health risk assessments,' during which additional diagnoses are added to the record — diagnoses that may never be treated or followed up on, but that trigger higher risk scores. Others have used chart review companies to comb through old medical records and add historical diagnoses. The OIG has found that certain diagnosis codes appear far more frequently in Medicare Advantage records than in Original Medicare records for comparable patients, with no corresponding increase in actual treatment. In plain terms: the paperwork says patients are sicker, but the care delivered doesn't reflect that.

For Original Medicare beneficiaries specifically, this matters in several concrete ways. First, the Medicare Trust Fund is a shared resource. The Hospital Insurance Trust Fund, which covers Part A (hospital care), is already projected to face funding shortfalls in the coming decade. Overpayments to Medicare Advantage plans accelerate that depletion. Second, Part B premiums — which cover outpatient care and are paid by virtually all Medicare beneficiaries, including those in Original Medicare — are set annually based on projected Medicare spending. When the overall Medicare program faces higher costs, those costs can feed into premium calculations. The standard Part B premium in 2025 was $185.00 per month, up from $174.70 in 2024. While many factors drive premium increases, program-wide overspending is among them. Third, resources diverted to overpayments are resources unavailable for expanding Original Medicare benefits, reducing cost-sharing, or adding dental and vision coverage that many beneficiaries want.

The federal government's primary tool for recovering overpayments is the Risk Adjustment Data Validation (RADV) audit program, run by the Centers for Medicare and Medicaid Services (CMS). RADV audits compare the diagnoses insurers submitted for payment against actual medical records to verify they're accurate. CMS finalized a major RADV audit rule in 2023 that was expected to recover billions in overpayments from contract years going back to 2018. However, major insurers including UnitedHealth Group and Humana — two of the largest Medicare Advantage carriers — have challenged these audits in federal court, arguing that the methodology CMS uses to calculate overpayments is flawed. As of mid-2026, litigation has slowed the recovery process significantly, and the full financial impact of the audits remains uncertain.

It's worth being clear about what this investigation does and doesn't mean if you're currently enrolled in a Medicare Advantage plan. Your individual benefits — your copays, your network, your drug coverage — are not directly affected by federal overpayment disputes. If you're happy with your Medicare Advantage plan and it's meeting your needs, this news is not a reason to panic or immediately switch. What it does mean is that the financial relationship between private insurers and the federal government is under serious scrutiny, and that scrutiny may lead to changes in how plans are paid, which could in turn affect what benefits they offer in future years. Medicare Advantage plans have historically used their overpayment cushion to fund extra benefits like dental, vision, and gym memberships. If payments are tightened, some of those extras may shrink — a trend already visible in 2025 and 2026 plan offerings, where several major insurers reduced supplemental benefits.

If you're currently on Original Medicare and wondering whether any of this should change your coverage decisions, here's the practical guidance: Original Medicare remains the baseline, and its coverage rules are set by federal law rather than by private insurers. You have guaranteed access to any provider who accepts Medicare, with no network restrictions. If you have a Medigap (Medicare Supplement) policy alongside Original Medicare, your out-of-pocket costs are highly predictable. The tradeoff is that Original Medicare has no cap on out-of-pocket costs without a Medigap policy, and it doesn't include prescription drug coverage unless you add a standalone Part D plan. Comparing your total annual costs — premiums plus expected out-of-pocket spending — between Original Medicare with Medigap and a Medicare Advantage plan is the most reliable way to evaluate your options.

The Annual Enrollment Period (AEP), running October 15 through December 7 each year, is your primary window to switch between Medicare Advantage and Original Medicare, or to change plans. If you switch from Medicare Advantage back to Original Medicare during AEP, be aware that Medigap insurers in most states can use medical underwriting — meaning they can charge you more or deny coverage based on your health history. There are 13 states with birthday rule protections (California, Idaho, Illinois, Kentucky, Louisiana, Maine, Maryland, Missouri, Nevada, New Jersey, New York, Oklahoma, and Oregon) that give you a 30-day window around your birthday each year to switch Medigap plans without medical underwriting. If you live in one of these states, that window can be a valuable opportunity to shop for better Medigap coverage regardless of your health status.

The broader policy debate over Medicare Advantage overpayments is far from resolved. Congressional proposals have ranged from strengthening RADV audits to restructuring the risk adjustment formula entirely. Advocacy organizations including the Medicare Rights Center and KFF (formerly the Kaiser Family Foundation) have published detailed analyses arguing that the current payment system creates structural incentives for upcoding that are difficult to eliminate without fundamental reform. Meanwhile, the insurance industry argues that risk adjustment payments are appropriate and that Medicare Advantage delivers value through care coordination and supplemental benefits that reduce overall healthcare costs. The truth, as with most complex policy debates, likely lies somewhere in between — but the documented pattern of overpayments is real, and its consequences for Medicare's long-term finances are serious. Staying informed about these developments, and reviewing your own coverage choices each enrollment period, remains the most powerful thing you can do as a beneficiary.