In March 2025, the Medicare Payment Advisory Commission — MedPAC, the nonpartisan federal body Congress created to advise on Medicare payment policy — delivered its annual report to Congress. Among the findings: the federal government paid $84 billion more for Medicare Advantage enrollees in 2025 than it would have cost to cover those same beneficiaries under traditional Medicare.
Eighty-four billion dollars. In a single year. From a single program.
That figure is not a projection or an estimate based on modeling assumptions. It is MedPAC’s calculation of the actual payment difference between what the government paid private MA insurers and what covering the same population under the traditional Medicare program would have cost. The government’s own accountants for Medicare calculated it, reported it to Congress, and noted that the overpayment has been growing — up from a $23 billion coding intensity component in 2023 to $40 billion in 2025 for that component alone.
The mechanism that generates the overpayment is called upcoding: the systematic documentation of diagnosis codes in Medicare Advantage enrollees’ medical records beyond what the treating providers documented, submitted to the government to inflate risk-adjusted payments for conditions that were recorded but not treated. It is not a marginal practice carried out by a rogue subset of the industry. It is a documented pattern across every major Medicare Advantage insurer — the rational organizational response to a payment structure that rewards diagnosis documentation regardless of care delivered.
This is the definitive platform treatment of Medicare Advantage upcoding. The Health Insurance Industry hub and Single-Payer Healthcare hub both address this subject; those treatments reference this article for comprehensive documentation.
The Three Mechanisms
Upcoding in Medicare Advantage operates through three primary mechanisms. Each has been documented in government audits, whistleblower litigation, and congressional investigation. Each is a variation on the same underlying logic: identify diagnosis codes that will increase the risk-adjusted payment, add them to the medical record through a process the insurer controls, and submit them to CMS without any requirement that the documented condition was treated or even clinically confirmed by the treating physician.
Retrospective chart reviews are the highest-volume mechanism. After care has been delivered — sometimes months after the patient encounter — the MA insurer or a vendor it contracts with systematically reviews medical records to identify conditions that were not submitted as diagnosis codes for risk adjustment. A retrospective reviewer who finds references to diabetes complications, heart failure staging, or cancer severity in a medical note that was not coded for risk adjustment flags those conditions for addition to the risk adjustment submission. The patient receives no follow-up care. The treating physician is not contacted to confirm the diagnosis. The condition is added to the submission and generates additional payment.
The review is conducted not to ensure the patient receives care for the identified conditions, but to ensure the insurer receives payment for having documented them. The distinction is the definitional element of upcoding: the documentation serves the payment, not the patient.
In-home health assessments are the mechanism that generates the most concentrated overpayment per encounter. The MA insurer dispatches a clinician — typically a nurse practitioner or physician assistant working for a vendor — to the beneficiary’s home to conduct a health assessment. The assessment generates a clinical encounter and a set of diagnosis codes that can be submitted for risk adjustment. The visiting clinician may document conditions the beneficiary’s regular physician has not coded — chronic kidney disease staging, depression, peripheral vascular disease — creating new HCC-eligible diagnoses from a single visit.
The assessment visit does not result in treatment. The visiting clinician does not become the patient’s treating provider. No referrals are made based on the newly documented conditions, or if referrals are made, they are not tracked as a condition of the payment the assessment generates. The insurer receives higher risk-adjusted payments for every month of the year based on diagnoses from a home visit that produced no treatment.
OIG has documented the in-home assessment model specifically as a high-risk mechanism for overpayment. The concern is not that health assessments are without clinical value — identifying undiagnosed conditions can benefit patients. The concern is that the mechanism as operated generates diagnosis codes for payment purposes without the clinical follow-through that would make those diagnoses therapeutically meaningful.
Chart review addenda are the most targeted mechanism. In this approach, the insurer or its vendor adds an addendum to an existing medical record — a note appended to a prior clinical encounter — that documents a diagnosis not captured in the original record. The addendum is attributed to the treating clinician’s record but generated through an insurer-initiated review process. The original clinical encounter did not code the condition. The addendum does. The addendum generates risk adjustment payment.
The addendum mechanism creates the clearest record of the gap between documentation and care: the treating clinician saw the patient, conducted the examination, documented the encounter, and did not code the condition. The insurer reviewed the record afterward, identified a billable diagnosis, and added it. Whether the treating clinician agreed with the addendum diagnosis, whether the patient was informed, whether any clinical follow-up occurred — none of those questions are prerequisites for the payment.
The Scale of Documentation
The OIG 2020 report that found 99 percent of the highest-value risk adjustment diagnoses were submitted by the insurer rather than the treating provider is not the only evidence of scale. The GAO documented approximately $75 billion in Medicare Advantage overpayments over the prior decade in its 2022 report. Early RADV audits — the CMS process for verifying that submitted diagnoses are supported by medical records — found average overpayment rates of over 10 percent of risk-adjusted payments for audited plans. CMS’s own coding intensity analysis found that the gap between MA diagnosis coding patterns and traditional Medicare coding patterns for the same population produces approximately $40 billion in annual overpayment from coding intensity alone.
The enforcement recovery against that documented scale is a fraction of the overpayment. Civil False Claims Act settlements — recoveries through litigation rather than audit — total several billion dollars across the industry over the same period in which the overpayment has accumulated in the hundreds of billions. The audit program that should be the primary correction mechanism has been constrained in scope and slowed by litigation over methodology. The political economy of rate reduction — documented in Article 02 and Article 12 — has prevented the benchmark rate corrections that would address the overpayment’s other component.
The gap between documented overpayment and enforcement recovery is not a technical failure of the audit process. It is the predictable consequence of an enforcement architecture that was not designed at the scale of the problem it was nominally intended to address.
Named Actors: The Pattern Across the Industry
The pattern of upcoding documented by government auditors and federal prosecutors is not confined to a single insurer or a subset of the industry. It runs across every major Medicare Advantage carrier. That pattern — across competitors, across markets, across years — is the evidence that what is documented is not misconduct by bad actors. It is the rational response of profit-maximizing organizations to a payment structure that rewards the behavior.
Kaiser Permanente settled the largest Medicare Advantage fraud case in history in 2023, agreeing to pay $556 million to resolve Department of Justice allegations that it had operated a years-long upcoding scheme. The DOJ alleged that Kaiser conducted retrospective chart reviews specifically to add diagnosis codes for conditions that were not being treated, generating inflated risk-adjusted payments. Kaiser did not admit wrongdoing as part of the settlement. The case was initiated by a whistleblower — a former Kaiser employee — under the False Claims Act’s qui tam provisions, which allow individuals with knowledge of fraud against the federal government to file suit on the government’s behalf and share in any recovery.
The $556 million settlement is the largest in MA fraud history. It is also a fraction of what the alleged conduct generated. A scheme that operated over multiple years across Kaiser’s large MA enrollment base would have produced risk-adjusted payment increases substantially exceeding the settlement amount. Civil settlements under the False Claims Act do not require disgorgement of all gains — they impose penalties and damages, but the penalty is not calibrated to recapture every dollar the conduct generated.
UnitedHealth Group faces criminal prosecution — not a civil settlement — for Medicare Advantage upcoding. The Department of Justice filed a criminal case in 2017 alleging that UnitedHealth systematically used chart reviews to add unsupported diagnosis codes to MA enrollees’ records to inflate risk-adjusted payments. Criminal prosecution of a Medicare Advantage insurer is significant for a specific reason: civil cases result in financial penalties; criminal cases can result in exclusion from federal healthcare programs. An insurer with $447.6 billion in 2025 revenue that is heavily dependent on government program payments — Medicare Advantage, Medicaid managed care, federal employee health plans — faces existential consequences from loss of government contract eligibility that no civil fine would impose.
A jury verdict in 2024 found for UnitedHealth on specific claims that went to trial. The broader litigation continued. The outcome of the full case — including the government’s remaining claims and any appeal — was not resolved as of the time this article was written.
While the DOJ criminal prosecution of the largest MA insurer was proceeding, the Trump administration simultaneously proposed a $13 billion increase in Medicare Advantage reimbursement rates for 2026. The administration that was criminally prosecuting UnitedHealth Group for extracting excess payments from Medicare Advantage proposed increasing the payments from which UnitedHealth had allegedly extracted its excess. That political contradiction requires no editorial characterization. The record speaks for itself.
Humana settled False Claims Act allegations in 2023 for $90 million, resolving claims that it had submitted unsupported diagnosis codes for risk adjustment purposes.
Cigna settled False Claims Act allegations in 2022 for $172 million on similar grounds.
CVS Health/Aetna was under active DOJ investigation for MA risk adjustment practices as of the time this article was written.
The four companies named above — UnitedHealth, Humana, Cigna, CVS Health/Aetna — are the four dominant Medicare Advantage insurers. Together they cover the substantial majority of MA enrollment. The Department of Justice has active or recently resolved actions against every one of them for the same category of conduct: submitting unsupported diagnosis codes to inflate risk-adjusted payments from a public program.
That is not a coincidence. It is a market.
The Congressional Record
In April 2026, a congressional budget hearing produced an exchange that documented bipartisan factual consensus on the Medicare Advantage fraud record. Representative Alexandria Ocasio-Cortez questioned Robert F. Kennedy Jr., then serving in a cabinet-level capacity, about Medicare Advantage upcoding and its cost to the program. Kennedy agreed that MA insurers were committing fraud through upcoding while simultaneously lowering provider reimbursement rates and increasing claim denials.
The exchange is significant not because bipartisan agreement that fraud is occurring resolves the policy question of what to do about it — it does not. It is significant as documentation that the factual record on MA upcoding has crossed the threshold of partisan contestation. Democrats and Republicans at a congressional hearing agreed, on the record, that what the government’s auditors have documented is happening. The policy responses they support differ. The underlying facts, as of April 2026, were not in dispute.
The Cost to Every Medicare Beneficiary
Medicare Part B premium — the monthly premium all Medicare beneficiaries pay for physician and outpatient coverage — rose from $185 per month in 2025 to $203 per month in 2026. The increase affects every Medicare beneficiary: those in traditional Medicare who never chose a private plan, those in Medicare Advantage, and those enrolled in MA who are also paying the Part B premium that underlies their coverage.
MedPAC has documented that Medicare Advantage overpayments increase total Medicare program costs, which are a factor in Part B premium calculations. A beneficiary who chose traditional Medicare over Medicare Advantage — who has no MA coverage and whose care is administered by a program paying providers directly with two percent administrative overhead — pays a higher monthly premium in part because the private insurers administering Medicare Advantage extracted $84 billion in excess payments from the program in the same year.
The overpayment is not contained within the MA program. It circulates through Medicare’s financing structure and returns as a premium increase paid by every beneficiary, including the ones who opted out.
The Central Irony
The political argument against government-administered healthcare has been consistent for decades: that government is inefficient, that private sector competition produces better outcomes at lower cost, that the discipline of the market corrects the waste that public programs institutionalize.
Medicare Advantage is the test of that argument within Medicare. Private insurers were brought into Medicare specifically to deliver its benefits more efficiently. The government pays them to administer what traditional Medicare would otherwise administer directly.
The government’s own accountants — MedPAC, operating under congressional mandate to advise on Medicare payment policy — calculate that the private insurers hired to make Medicare more efficient extracted $84 billion in excess payments from the program in a single year. The Department of Justice has filed criminal charges against the largest of those insurers for the mechanism by which a substantial portion of that excess was generated.
The argument that government cannot run healthcare efficiently is being made, in current congressional testimony and in industry lobbying, by entities that extracted $84 billion from the government program they were hired to administer more efficiently than the government could.
That is the record. What to do about it is the subject of Articles 12 and 13.
The complete Medicare Advantage series
01 — What Medicare Advantage Actually Is — and How It Replaced Traditional Medicare
02 — The Political History: How Private Insurers Got Into Medicare
03 — The Marketing Machine: How Enrollment Works and Who It Targets
04 — Risk Adjustment: The Payment System That Rewards Diagnosis, Not Treatment
05 — The $84 Billion Overpayment: How Upcoding Works at Scale
06 — The Profit Extraction Model: What Insurers Take Before Care Is Delivered
07 — Prior Authorization in Medicare Advantage: What OIG Found
08 — The Denial and Appeals Record: What Happens When Enrollees Push Back
09 — Network Adequacy and the Coverage Gap
10 — The Extra Benefits Myth: Dental, Vision, and What the Fine Print Says
11 — When Medicare Advantage Fails: Disenrollment at the End of Life
12 — The Reform Proposals: From Audit Reform to Elimination
13 — What the Evidence Resolves — and What It Doesn’t
This article was researched and drafted with AI assistance under human review. See our full AI and editorial practices.