UnitedHealth Group is under a criminal investigation by the US Department of Justice (DOJ) over its handling of Medicare Advantage billing practices, according to individuals familiar with the matter.
The probe, led by the DOJ’s criminal healthcare-fraud unit, has reportedly been active since at least mid-2023 and focuses on potential misconduct within UnitedHealth’s Medicare Advantage operations.
Although the DOJ has not publicly confirmed the investigation, sources indicate it is part of a broader shift in enforcement that includes greater scrutiny of insurers participating in the Medicare Advantage program. Traditionally, this DOJ unit has pursued providers such as doctors and laboratories for overbilling Medicare. However, recent efforts have expanded to include large insurance firms, which now manage healthcare benefits for more than half of the country’s Medicare beneficiaries.
UnitedHealth, one of the largest private insurers in the US, stated that it had not been notified by the DOJ about any criminal investigation and stood “by the integrity of our Medicare Advantage program.” A DOJ spokesperson declined to comment.
The federal inquiry adds to a growing list of regulatory challenges facing UnitedHealth. The company is also under civil and antitrust investigation, including scrutiny of Medicare billing and a proposed acquisition of home healthcare provider Amedisys Inc. In addition, UnitedHealth’s Medicare Advantage billing practices have drawn attention from Congress. Earlier this year, lawmakers raised concerns during confirmation hearings for new Medicare and Medicaid chief Dr. Mehmet Oz, who pledged a crackdown on improper billing practices within the program.
The investigation comes during a period of heightened instability for the company. On Tuesday, UnitedHealth unexpectedly replaced its CEO, Andrew Witty, with former CEO and current chairman Stephen Hemsley. The move followed a series of difficulties, including the company suspending its 2025 earnings guidance and reporting weaker financial performance attributed to increased medical costs. UnitedHealth’s stock has fallen nearly 50% in recent weeks, including an 8% drop in after-hours trading following news of the DOJ investigation.
A Wall Street Journal investigation previously reported that some Medicare Advantage insurers, including UnitedHealth, may have submitted diagnosis codes that exaggerated patients’ illnesses, resulting in billions in extra payments from the federal government. UnitedHealth disputed those findings, calling the analysis inaccurate and defending the Medicare Advantage model as providing better outcomes at lower cost.
One long-standing civil case against UnitedHealth, joined by the DOJ in 2017, alleges that the company overbilled Medicare by submitting unsupported diagnoses. A special master recently recommended dismissing the case, stating the DOJ had not sufficiently proven its claims. UnitedHealth interpreted the recommendation as confirmation that there was no evidence of wrongdoing, although the judge has not yet ruled on the matter.
Meanwhile, internal company emails referenced in investor litigation show that UnitedHealth was aware the government had been asking questions about its Medicare coding practices. A company attorney described the probe as being in its early stages and cautioned a former employee about potential outreach from investigators.
This wave of scrutiny coincides with broader efforts by the Trump administration and Congress to rein in federal healthcare spending. Nearly half of all Medicare beneficiaries are now enrolled in Medicare Advantage plans, which pay insurers more for covering patients with more complex health needs. Critics argue that some insurers manipulate the system to boost payments, while defenders say the model delivers more coordinated and cost-effective care.
With input from the Wall Street Journal, Bloomberg, CNBC, and Investor’s Business Daily.