U.S. Senate Accuses UnitedHealth of Stonewalling Probe as Medicare Fight Escalates

Tensions between Washington and America’s largest health insurer escalated on Monday, as senior U.S. lawmakers accused UnitedHealth Group (UNH) of failing to fully cooperate with a congressional inquiry into its Medicare billing practices and its use of automated tools in claims decisions.

In a sharply worded letter addressed to CEO Andrew Witty, Senators Ron Wyden and Elizabeth Warren said the company has not provided certain information and documentation requested by investigators. The senators also raised concerns about the insurer’s use of artificial intelligence and predictive analytics in decision-making related to patient care coverage.

The dispute follows heightened scrutiny of Medicare Advantage plans across the industry, particularly around allegations that algorithmic systems may influence coverage determinations in ways that could restrict access to post-acute care for older patients.

Market reaction

UnitedHealth shares traded lower in premarket activity on Monday as investors weighed the latest political and regulatory pressure. The stock has shown increased volatility in recent weeks amid broader uncertainty over Medicare Advantage profitability and shifting regulatory oversight.

Several insurers have also scaled back participation in certain Medicare Advantage markets going into 2026, citing rising medical costs, reimbursement pressures, and performance challenges in specific counties—raising questions about how competitive dynamics and access could evolve in the program.

The “black box” of AI denials

At the centre of the dispute is UnitedHealth subsidiary naviHealth, which helps manage post-acute care. Lawmakers and patient advocates have alleged that predictive tools may have been used to override clinician recommendations or accelerate discharge timelines—claims that UnitedHealth has disputed in past reporting.

Senators Wyden and Warren argued that the company’s response to document requests has been insufficient, limiting the ability of investigators to fully assess how automated tools are used in Medicare-related coverage decisions.

The broader issue is increasingly becoming a policy flashpoint: as insurers and healthcare operators deploy advanced analytics to reduce costs, lawmakers and regulators are pushing for stronger transparency into how these models work and whether they produce systemic denial patterns.

Federal authorities have also been reviewing broader aspects of UnitedHealth’s business practices, including its scale and ownership across insurance, pharmacy benefits, and healthcare services—an area that has attracted growing attention in Washington.

Summary

U.S. Senators Ron Wyden and Elizabeth Warren accused UnitedHealth of failing to fully comply with a congressional information request related to Medicare billing practices and the use of AI-driven systems in coverage decisions. The dispute centres partly on subsidiary naviHealth and concerns about algorithmic influence on post-acute care. UnitedHealth shares slipped in premarket trading as regulatory scrutiny across Medicare Advantage intensifies.

Frequently asked questions (FAQs)

Q1: What are lawmakers accusing UnitedHealth of?

Senators said UnitedHealth has not provided certain information and documents requested as part of a congressional inquiry into Medicare-related practices and the use of automated tools in coverage decisions.

Q2: What role does AI play in this issue?

Lawmakers are focused on whether predictive technologies or algorithmic tools are being used in a way that affects medical coverage outcomes—such as approvals, denials, or length-of-care determinations—particularly for post-acute care.

Q3: What is naviHealth and why is it mentioned?

naviHealth is a UnitedHealth subsidiary involved in coordinating and managing post-acute care services. It has faced scrutiny in prior reporting related to how predictive tools may influence care authorisations.

Q4: Is this investigation criminal?

This draft refers to congressional oversight and broader federal scrutiny. While multiple agencies have reviewed UnitedHealth’s practices in various areas, not every inquiry is criminal. UnitedHealth has generally disputed allegations and said it operates within applicable rules.

Q5: Why are Medicare Advantage insurers under pressure in 2026?

Many insurers are facing tighter margins due to rising healthcare costs, reimbursement changes, and closer regulatory scrutiny. Some carriers have reduced their presence in selected counties due to profitability pressures.

Q6: How could this affect policyholders?

If regulators require greater transparency or changes to coverage practices, insurers may need to adjust how claims are reviewed. In some regions, reduced plan availability could also impact consumer choice.