OIG Finds $180M in Medicare Advantage Overpayments

Federal Audit Finds Nearly $180 Million in Medicare Advantage Overpayments

The U.S. Department of Health and Human Services Office of Inspector General (HHS OIG), the federal watchdog responsible for auditing Medicare spending, reported on September 17, 2026, that two Medicare Advantage plan contracts, HumanaChoice and UnitedHealthcare of Wisconsin, frequently overstated the severity of members' health conditions in ways that generated close to $180 million in overpayments over a two-year period, according to Healthcare Dive. Medicare Advantage (MA) is the private-plan alternative to Original Medicare, in which the federal government pays participating insurers a fixed monthly amount per enrollee that rises when a member is documented with more serious diagnosed conditions.

That per-member payment adjustment, known as risk adjustment, is the mechanism OIG's audit examined. According to the audit findings summarized by Healthcare Dive, diagnosis codes submitted for a sample of enrollees in these two plans did not match what supporting medical records could confirm, a billing pattern regulators refer to as upcoding, meaning a condition is coded as more severe than documentation supports, which triggers a higher federal payment for that member. The supplied source material does not include a public response from Humana or UnitedHealthcare, and insurers named in OIG risk-adjustment audits generally have the ability to dispute individual findings and contest proposed repayment amounts through CMS's formal audit and appeals process before any final recovery is determined.

Why Risk Adjustment Audits Keep Surfacing at Large Insurers

HHS OIG has conducted a series of contract-level risk adjustment audits across large Medicare Advantage insurers in recent years, and this report continues that pattern rather than representing an isolated incident tied only to these two plans. The audits work by pulling a sample of enrollees' diagnosis codes and checking them against the medical record documentation on file, then extrapolating any mismatch rate across the full contract to estimate total overpayments. A finding of nearly $180 million across two plan contracts over two years is a substantial figure in dollar terms, but it reflects an accounting and documentation dispute between the insurer and CMS rather than a finding about clinical care quality or member safety.

What Overpayment Findings Do, and Do Not, Change for Enrollees

An OIG overpayment finding does not automatically change premiums, provider networks, or covered benefits for people currently enrolled in HumanaChoice or UnitedHealthcare of Wisconsin plans. CMS recovery of confirmed overpayments happens between the agency and the insurer, separate from a member's individual coverage. That said, sustained scrutiny of an insurer's risk adjustment practices is one data point worth weighing alongside more direct measures of plan quality, such as CMS Star Ratings, formal complaint rates, and network adequacy, when comparing options.

What Medicare Advantage Shoppers Should Do Before the 2026 Fall Enrollment Period

The Medicare Annual Enrollment Period runs October 15 through December 7, 2026, when current enrollees can switch Medicare Advantage plans, move to a different Part D prescription drug plan, or return to Original Medicare. For readers weighing HumanaChoice, UnitedHealthcare of Wisconsin, or any other Medicare Advantage plan this fall, a few practical steps apply regardless of this audit news. First, review the plan's current CMS Star Rating and any recent complaint history on Medicare.gov's Plan Finder tool, since that data reflects member experience more directly than a billing audit does. Second, confirm that your specific doctors, hospitals, and prescription drugs are still covered under the plan's 2027 network and formulary, since those details can change year to year even when a plan's name stays the same. Third, if you are also comparing Medicare Advantage against Original Medicare paired with a Medicare Supplement (Medigap) policy, remember that the two paths involve different tradeoffs around network restrictions, out-of-pocket cost predictability, and referral requirements, separate from any billing dispute between a specific insurer and CMS. Because plan details, costs, and audit outcomes can shift, readers comparing Medicare Advantage options this fall should review current plan documents directly or speak with a licensed Medicare agent before making a coverage decision, rather than relying on a single audit report to judge overall plan quality.