Major health insurers are taking legal action against Radiology Partners, the nation’s largest radiology group, alleging the company systematically billed out-of-network rates for services performed at in-network facilities. Aetna filed suit in December 2024 in the U.S. District Court for the Middle District of Florida, accusing Radiology Partners of a “multiphase healthcare fraud scheme” that funneled over 110,000 claims through a single entity to inflate reimbursement, resulting in more than $20 million in payments Aetna says were undeserved. UnitedHealthcare followed with its own lawsuit in August 2025 in Arizona, alleging the radiology giant created a “sham out-of-network entity” that billed for 714 physicians who already had in-network agreements.
These lawsuits strike at a growing tension in American healthcare: the collision between private-equity-backed provider consolidation and the federal No Surprises Act’s Independent Dispute Resolution process. Radiology Partners, backed by private equity, allegedly exploited the IDR arbitration system to extract payments sometimes exceeding 1,000% of Medicare rates, according to UnitedHealthcare’s complaint. Aetna goes further, alleging that Radiology Partners is responsible for over 90% of all IDR cases involving professional radiology services nationwide.
Table of Contents
- How Did a Radiology Group Bill Out of Network at In-Network Facilities?
- The No Surprises Act and How IDR Arbitration Became a Battleground
- The Financial Scale of the Alleged Billing Scheme
- What Patients Should Know About Out-of-Network Radiology Billing
- Private Equity’s Role in Healthcare Billing Disputes
- How These Cases Could Reshape the IDR Process
- What Comes Next for Radiology Billing and Consumer Protections
- Frequently Asked Questions
How Did a Radiology Group Bill Out of Network at In-Network Facilities?
The mechanics of the alleged scheme differed slightly between the Florida and Arizona cases, but the core strategy was the same: route in-network claims through an entity that could bill at out-of-network rates, then use federal arbitration to demand higher payments. In Florida, Aetna alleges that Radiology Partners funneled billing for all its Florida-affiliated radiology practices under the taxpayer identification number of Mori, Bean and Brooks (MBB), a single entity that held the most favorable in-network contract rates. The number of physicians billing under MBB’s TIN ballooned from roughly 50 in September 2018 to over 1,000, according to the complaint. In Arizona, UnitedHealthcare alleges Radiology Partners took a different but parallel approach. The insurer claims RP created an entity called Sonoran Radiology — originally incorporated as Red Rock Imaging Associates in 2019 — specifically to serve as an out-of-network billing vehicle.
Services performed by physicians affiliated with groups that already held in-network UHC contracts were instead billed through Sonoran at out-of-network rates. RP had previously acquired Scottsdale Medical Imaging in 2017 and Sun City Imaging in 2018, both of which carried UHC contracts, making the alleged switch to out-of-network billing through a new entity particularly notable. The distinction matters for consumers. When a patient goes to an in-network hospital and receives radiology services, they reasonably expect those services to be covered at in-network rates. If the radiology group bills through an out-of-network entity, the patient can face surprise bills or higher cost-sharing — exactly the kind of scenario the No Surprises Act was designed to prevent.
The No Surprises Act and How IDR Arbitration Became a Battleground
The No Surprises Act, which took effect in January 2022, was meant to protect patients from unexpected medical bills when they receive care from out-of-network providers at in-network facilities. The law created an Independent Dispute Resolution process where insurers and providers can settle payment disagreements through binding arbitration rather than sticking the patient with the bill. However, these lawsuits suggest that the IDR process itself may be vulnerable to exploitation. In the Florida case, Aetna alleges the scheme had two distinct phases. In Phase 1, Radiology Partners consolidated billing under MBB’s favorable in-network contract. After Aetna caught on and terminated MBB’s in-network contract, Phase 2 began: RP continued billing through MBB as an out-of-network provider and then used the IDR process to seek even higher payments than the original in-network rates.
Aetna claims this generated “tens of thousands” of arbitration proceedings. The sheer volume is staggering — Aetna alleges Radiology Partners accounts for over 90% of all IDR cases involving professional radiology services nationally. There is an important limitation to understand here. The No Surprises Act was designed with good intentions, and the IDR process works as intended in many legitimate billing disputes between insurers and providers. However, if these allegations prove true, they illustrate how a well-resourced entity can weaponize a consumer protection mechanism for profit. Legal analysts note that the outcome of these cases could reshape how the IDR process functions going forward, potentially leading to new safeguards or eligibility requirements for arbitration filings.
The Financial Scale of the Alleged Billing Scheme
The dollar figures in these lawsuits reveal just how lucrative the alleged out-of-network billing strategy was. In the Florida case, Aetna claims that over 110,000 claims were billed under MBB’s taxpayer identification number, resulting in more than $20 million in payments that Aetna says MBB was never entitled to receive. Aetna characterized the entire operation as “purely profit-driven.” UnitedHealthcare’s Arizona lawsuit paints an equally troubling financial picture. The insurer alleges that reimbursements to Radiology Partners through the Sonoran Radiology entity sometimes exceeded 1,000% of Medicare rates — meaning RP received more than ten times what Medicare would have paid for the same services.
Beyond the inflated reimbursements themselves, UHC claims that it and its employer customers paid over $24 million in administrative fees related to “ineligible IDR disputes” initiated by Radiology Partners since January 2022. Those administrative costs alone represent a significant financial burden that gets passed along to employers and, through higher premiums, to patients. To put this in perspective, a radiology reading that Medicare might reimburse at $50 could have been billed at $500 or more through the alleged out-of-network arrangement. For a group handling tens of thousands of claims per year, the arithmetic adds up quickly. The combined alleged damages across both lawsuits — direct overpayments plus administrative costs — exceed $44 million, and those figures may represent only a portion of the total financial impact across all insurers.
What Patients Should Know About Out-of-Network Radiology Billing
For consumers, the practical question is straightforward: what should you do if you receive an unexpected bill from a radiology group after visiting an in-network facility? The No Surprises Act provides meaningful protections, but understanding them requires knowing the difference between what the law covers and what it does not. Under the No Surprises Act, if you receive emergency services or are treated by an out-of-network provider at an in-network facility, you generally cannot be billed more than the in-network cost-sharing amount. The billing dispute is supposed to happen between the provider and the insurer, not land on your kitchen table. If you do receive a surprise bill in this situation, you have the right to dispute it. Contact your insurer first to confirm the facility was in-network, then file a complaint with the Centers for Medicare and Medicaid Services or your state’s insurance department.
However, there is a tradeoff worth understanding. While the No Surprises Act shields patients from the immediate financial hit of surprise bills, the underlying cost inflation — if these allegations are accurate — still affects consumers indirectly. Higher reimbursements and administrative costs get baked into insurance premiums. So even if you never personally receive a surprise radiology bill, you may be paying for inflated radiology costs through higher monthly premiums. This is one reason why the outcome of these lawsuits matters beyond the courtroom.
Private Equity’s Role in Healthcare Billing Disputes
These lawsuits are not occurring in a vacuum. Radiology Partners is the nation’s largest radiology group and is backed by private equity investors. Both Aetna’s and UnitedHealthcare’s complaints specifically reference the role of private equity in driving the alleged billing practices. Aetna’s suit names RP’s private equity backers as defendants alongside the company itself. Legal analysts have noted that these cases highlight a broader tension between health plans and private-equity-backed provider consolidation.
When a private equity firm acquires multiple medical practices in a region, it gains use that individual practices never had. That consolidation can lead to legitimate efficiencies, but it can also create the market power to push billing practices that maximize revenue at the expense of insurers and, patients. The pattern alleged in these lawsuits — acquire in-network practices, shift billing to an out-of-network entity, then use arbitration to demand higher payments — would be difficult for a single small practice to execute but becomes viable at scale. A word of caution: not every private-equity-backed healthcare company engages in questionable billing practices, and consolidation sometimes does deliver better care coordination and technology investment. But the pattern of allegations here, involving the nation’s largest radiology group and two of the nation’s largest insurers, suggests that regulators and lawmakers may need to look more closely at how ownership structures influence billing behavior. Radiology Partners has firmly denied the allegations, stating this is “yet another example of a troubling trend where payors lose in the federal No Surprises Act arbitration process and then turn to litigation.”.
How These Cases Could Reshape the IDR Process
The outcome of these lawsuits could have lasting consequences for how the No Surprises Act’s dispute resolution system operates. If the courts rule that Radiology Partners improperly used the IDR process, it could prompt regulatory changes that tighten eligibility requirements for arbitration filings. For example, regulators might require that providers demonstrate they are genuinely out-of-network — not simply billing through an out-of-network shell entity — before initiating IDR proceedings.
There is already pressure on the system. The volume of IDR filings has far exceeded what the government originally anticipated, creating backlogs and administrative strain. If Aetna’s claim is accurate that a single company accounts for over 90% of IDR cases in an entire medical specialty, that concentration alone suggests the process may need structural reform to function as Congress intended.
What Comes Next for Radiology Billing and Consumer Protections
Both lawsuits are still in their early stages, and the courts have not yet ruled on the merits of either case. Radiology Partners maintains its position that insurers are turning to litigation after losing in the IDR arbitration process. The company’s defense suggests these cases will be hard-fought, with significant resources on both sides.
Regardless of how the courts rule, these cases have already drawn attention to vulnerabilities in the No Surprises Act framework. Consumers should expect continued scrutiny of radiology billing practices and potential legislative or regulatory action to close loopholes in the IDR process. For now, the best thing patients can do is review every medical bill carefully, verify that services billed as out-of-network were actually performed by out-of-network providers, and file complaints when something does not add up. The protections exist, but they only work when patients know to use them.
Frequently Asked Questions
What is the No Surprises Act and how does it protect me from out-of-network radiology bills?
The No Surprises Act, effective since January 2022, generally prohibits out-of-network providers from billing patients more than in-network cost-sharing amounts when services are performed at in-network facilities. If a radiology group bills you at out-of-network rates for services at an in-network hospital, the billing dispute should be between the provider and insurer, not passed to you.
What should I do if I receive a surprise bill from a radiology group?
First, confirm with your insurer that the facility where you received services is in-network. If it is, the No Surprises Act likely applies. Contact your insurer to dispute the charge, and if it is not resolved, file a complaint with the Centers for Medicare and Medicaid Services or your state insurance department.
What is Radiology Partners accused of in these lawsuits?
Aetna and UnitedHealthcare allege that Radiology Partners funneled in-network radiology services through out-of-network billing entities to collect higher reimbursements. In Florida, this allegedly involved over 110,000 claims and $20 million in overpayments. In Arizona, reimbursements allegedly exceeded 1,000% of Medicare rates. Radiology Partners denies these allegations.
How does the IDR arbitration process work under the No Surprises Act?
When an insurer and out-of-network provider cannot agree on payment, either party can initiate Independent Dispute Resolution. A neutral arbitrator reviews both sides’ proposed payment amounts and selects one. The process was designed to resolve billing disputes without involving the patient, but these lawsuits allege it has been exploited for profit.
Does Radiology Partners have a settlement fund or claims process for affected patients?
As of now, these are lawsuits between insurers and Radiology Partners, not class action settlements with consumer claims processes. There is no settlement fund or claims deadline for patients at this stage. If a settlement is reached that includes patient compensation, it would be announced through the court.
Are other radiology groups or medical specialties facing similar allegations?
While these lawsuits specifically target Radiology Partners, the billing pattern alleged — using shell entities to convert in-network services to out-of-network billing — could theoretically occur in any medical specialty where providers are separate from facilities. Legal analysts expect these cases to set precedents that affect billing practices across healthcare.