Radiology Partners Lawsuit: Aetna, UHC, and Pass-Through Billing

The Radiology Partners lawsuit landscape centers on two federal cases: one brought by Aetna in Florida in December 2024 and one brought by UnitedHealthcare in Arizona in August 2025. Both insurers accuse the country’s largest radiology practice of exploiting the No Surprises Act arbitration process through a pass-through billing scheme to collect inflated out-of-network payments. A federal judge dismissed Aetna’s case with prejudice in April 2026, and Aetna has appealed. UnitedHealthcare’s case is still pending.¹²

The Common Allegation: Pass-Through Billing Through Out-of-Network Affiliates

The two lawsuits describe the same basic pattern in different states. Radiology Partners acquires radiology groups that hold in-network contracts with a major insurer. Services performed by physicians at other Radiology Partners locations are then billed through a different affiliate whose contract status produces a higher payment. Tens of thousands of resulting claims are pushed into the independent dispute resolution (IDR) process created by the No Surprises Act, where arbitrators pick between the provider’s and insurer’s proposed payment amounts.³⁴

Radiology Partners denies wrongdoing in both cases. The company has framed the suits as insurer efforts to escape arbitration outcomes they lost, saying payers “dissatisfied with IDR results” are trying to “attack those outcomes outside the framework Congress created.”⁵

Aetna’s Florida Lawsuit

Aetna, a subsidiary of CVS Health, filed suit against Radiology Partners and its Florida affiliate Mori, Bean and Brooks Inc. (MBB) on December 23, 2024, in the U.S. District Court for the Middle District of Florida (Case No. 3:24-cv-01343).⁶

What Aetna Alleged

Aetna’s complaint described a two-phase scheme. Radiology Partners acquired MBB, a Jacksonville practice with one of Aetna’s most lucrative in-network Florida contracts, in 2018. After the acquisition, Aetna alleged, the company began using MBB’s tax identification number to bill for services performed by radiologists at other Florida locations who were not part of MBB, effectively routing those claims through MBB’s higher reimbursement rates.³

By 2022 Aetna noticed the uptick and asked Radiology Partners about it. Aetna alleged the company deflected the inquiries, and Aetna then terminated its in-network contract with MBB. According to the complaint, Radiology Partners kept billing through MBB’s now-out-of-network tax ID rather than routing claims through affiliated Florida practices that still had in-network agreements, and then filed tens of thousands of IDR disputes to collect higher out-of-network amounts.⁵

Aetna alleged more than 110,000 improperly billed claims and wrongful payments exceeding $20 million. The complaint asserted fraud, negligent misrepresentation, civil conspiracy, unjust enrichment, and violations of ERISA and the No Surprises Act, and it invoked Florida’s corporate practice of medicine laws.³

Dismissal and Appeal

On April 16, 2026, U.S. District Judge Brian J. Davis dismissed Aetna’s lawsuit with prejudice, meaning Aetna cannot refile the same claims. Judge Davis ruled that Aetna failed to meet the high bar for challenging arbitration awards under the Federal Arbitration Act and that concerns about billing practices should have been raised during the IDR process rather than through separate litigation. Arbitration outcomes, the court said, carry significant deference and can be overturned only in narrow circumstances such as fraud or arbitrator misconduct, neither of which Aetna established. The court also noted Aetna knew about the billing practices at issue but did not raise them during arbitration.⁷¹

Aetna filed a notice of appeal on May 6, 2026.⁶

UnitedHealthcare’s Arizona Lawsuit

UnitedHealthcare sued Radiology Partners and its Arizona affiliate Sonoran Radiology Ltd. on August 8, 2025, in the U.S. District Court for the District of Arizona (Case No. 2:25-cv-02862).²

UHC’s version of the scheme runs in the opposite direction from Aetna’s. According to the complaint, Radiology Partners acquired established Arizona groups — including Scottsdale Medical Imaging and Sun City Imaging — that already held in-network UHC contracts at lower negotiated rates. Beginning in 2021, the company allegedly routed services performed by physicians at those in-network groups through Sonoran Radiology, an out-of-network entity, making the claims appear eligible for higher out-of-network reimbursement. UHC accused Radiology Partners of then flooding IDR with tens of thousands of these claims while submitting false certifications to arbitrators and to the Department of Health and Human Services attesting the services were genuinely out-of-network.⁴

UHC alleged that it and its employer customers paid over $24 million in administrative fees on ineligible IDR disputes since January 2022. The complaint alleged Radiology Partners sought payments approaching 1,600% of Medicare rates and received IDR awards exceeding 600% of median in-network rates, and that 714 physicians affiliated with groups holding existing in-network UHC agreements were involved.⁴

The 12-count complaint includes RICO Act claims, ERISA violations, fraud, negligent misrepresentation, civil conspiracy, and unjust enrichment. UHC seeks compensatory and punitive damages, reversal of past arbitration awards, and a jury trial.⁸

Radiology Partners has said it will “vigorously defend” against the claims.⁹ In November 2025 the defendants filed a motion to stay, transfer, or dismiss the case, arguing in part under the first-to-file rule, likely pointing to overlap with the pending Aetna case in Florida, and alternatively seeking dismissal for failure to state a claim. As of June 2026, Senior Judge G. Murray Snow had not ruled on that motion, and the case remains active.²

Why the IDR Process Is at the Heart of Both Cases

The No Surprises Act, effective in 2022, created an independent dispute resolution process for out-of-network payment disagreements between insurers and providers. After 30 days of failed negotiation, either party can initiate IDR, both sides submit a proposed payment amount, and a government-certified arbitrator picks one.¹⁰

Federal officials originally expected about 17,000 disputes a year. By the first half of 2025, 4.8 million cases had been filed. Providers initiated virtually all of them and won 88% in early 2025.¹¹

Radiology Partners is the single largest initiator in that system. In the second half of 2024 alone the company filed 136,784 IDR disputes, more than 90% of all IDR cases involving professional radiology services. Radiology Partners reports winning 98% of its disputes against Aetna, and industry-wide the average prevailing payment in radiology IDR has been roughly 535% of the qualifying payment amount, the benchmark representing the median in-network rate.¹²

Those numbers explain the shape of the litigation. Both insurers are arguing not just that they overpaid on individual claims but that the volume and characterization of claims funneled into IDR was itself the mechanism of the alleged fraud. The Florida ruling suggests the courts may treat that as an argument that should have been made inside the arbitration process rather than after it.⁷

The Earlier Texas Arbitration

UHC and Radiology Partners have fought over the same billing theory before, in a separate Texas arbitration. In April 2022, Singleton Associates PA, a Radiology Partners affiliate, filed a demand with the American Arbitration Association alleging systematic underpayment by UHC of Texas and initially seeking more than $100 million. UHC countered that Radiology Partners had engaged in pass-through billing by using radiologists from different branches to bill through affiliates with higher negotiated rates.¹³

The three-member panel initially awarded Radiology Partners $153.5 million, including $134.3 million in underpayment damages, interest, and fees. After changes in panel membership, the reconstituted panel reached a different conclusion in August 2024: UHC owed Radiology Partners $94.3 million in underpayments, but the radiology group could not recover any of it because it had breached the underlying 1998 agreement. The panel also denied UHC any recovery against Singleton, leaving neither side entitled to relief.¹³

The Texas record matters for what comes next. In Florida, Radiology Partners argued that a Texas arbitrator had already rejected the same tort theories Aetna was now raising, and that Aetna had itself previously argued non-signatory Radiology Partners affiliates were bound by similar arbitration clauses.¹⁴ Whether the Arizona court reaches those arguments will depend on how it rules on the pending motion to dismiss or transfer.

1
Healthcare Dive. Judge Dismisses Aetna Lawsuit Against Radiology Partners
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Radiology Business. Judge Dismisses CVS Aetna’s Lawsuit Against Radiology Partners
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BenefitsPro. Court Shuts Down Aetna Challenge to Radiology Arbitration Awards
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Radiology Business. UnitedHealthcare Sues Radiology Partners Again, Claiming Mega-Practice Weaponized Surprise Billing
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Becker’s Payer Issues. UnitedHealthcare Sues Radiology Partners Over No Surprises Claims
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American College of Radiology. Independent Dispute Resolution Under the No Surprises Act: The Basics
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Georgetown University Center on Health Insurance Reforms. The No Surprises Act IDR Process: An Early Look at 2025 Data
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Radiology Business. Radiology Partners No. 1 Initiator of No Surprises Act Disputes, CMS Says
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Radiology Business. Arbitrators Settle Radiology Partners-UnitedHealthcare Dispute, Vacating $134M Award
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Innovate Healthcare. Motion to Compel Arbitration