Radiologists continue to dominate in No Surprises Act payment disputes

Radiologists and other physicians continue to dominate in payment disputes with health insurers under the No Surprises Act. 

The federal government recently released new data pertaining to the landmark legislation, meant to protect patients from receiving unexpected medical bills. It shows that providers won about 88% of such disagreements relating to out-of-network care in the first half of 2025. 

Emergency department services accounted for the greatest share of payment determinations at 45%, followed by radiology at 19%, according to the Centers for Medicare & Medicaid Services. Altogether, there were 1.9 million disputes submitted through the independent dispute resolution, or IDR, portal between January and June, a 39% uptick versus the previous six months. 

“Certified IDR entities continued their efforts to scale up their operations to contend with the large volume of disputes,” CMS reported in information dated Jan. 21, noting they are “making substantially more payment determinations in the first six months of 2025 compared to the last six months of 2024.”

Providers instigated most of the disputes (81%) in the first half of 2025, and healthcare facilities initiated a higher share of these quarrels (19%) compared to the previous year (13%). As was the case with the last data release, most payment disputes were initiated by a limited number of parties and their representatives. Altogether, the top 10 initiating parties accounted for 69% of all payment disputes, similar to 2024’s second half (71%). 

Radiology Partners, the country’s largest imaging group, was No. 3 in the first quarter of 2025, launching over 63,000 disputes (or 12%). RP landed at No. 4 in Q2, initiating nearly 48,000 disputes (or 8%). HaloMD, a Texas-based entity that handles disputes on behalf of providers, was No. 1 both quarters, followed by TeamHealth, a multispecialty care group out of Tennessee. Rad Partners was previously listed as the No. 1 initiator, based on data from the second half of 2024.

Congress enacted the No Surprises Act in 2020, and it took effect on Jan. 1, 2022, seeking to protect patients from surprise medical bills. Under the NSA, independent arbitrators are tasked with mediating disputes between commercial health insurers and healthcare providers that are out of their coverage networks. On the payer side, the country’s largest commercial insurer, UnitedHealthcare, was involved in the most disputes in the first half of 2025, at 334,681. Blue Cross and Blue Shield of Texas was the next closest with 181,379, followed by Aetna at 143,039, and MultiPlan/Claritev with 134,654.  

Radiology Partners’ use of the IDR process is the subject of litigation between the imaging group and both Aetna and UnitedHealthcare. The former sued RP in December 2024, claiming after it kicked an affiliated practice out of network, the radiology group improperly flooded the system with tens of thousands of disputes. Rad Partners—which is backed by Whistler Capital Partners and New Enterprise Associates—responded in February, noting it has won 98% of disagreements with Aetna, believing the payer is trying to push around providers to pad profits. UnitedHealthcare later did the same thing in August, claiming RP has “weaponized” surprised billing protections. 

“This is yet another example of a broader and troubling trend: When payers lose in the federal No Surprises Act arbitration process, they turn to litigation,” Rad Partners said last year in response to the allegations. “UHC’s complaint misrepresents the facts and distracts attention from its repeated failures to pay healthcare professionals despite federal protections.”

More on new data

The American College of Radiology also shared the latest data in a news update published Thursday. About 87% of awards exceeded the qualifying payment amount, a median in-network rate calculated by payers, ACR reported. 

Along with releasing the new information, the federal government also has certified a new IDR entity, Dane Street LLC. This expands the number of such arbitrators up to 16, with expectations this will “increase IDR throughput and reduce an ongoing backlog of determinations,” ACR added. 

Sens. Bill Cassidy, MD, R-La., head of the Health, Education, Labor, and Pensions (HELP) Committee, and Maggie Hassan, D-N.H., also recently sent a letter to HHS regarding surprise billing. They expressed support for the federal government’s efforts to improve implementation of the No Surprises Act while calling for the finalization of pending rules aimed at further strengthening operations. 

“We are concerned that the fees that providers and plans pay to initiate disputes—regardless of whether the claim is eligible or ineligible—could drive up the cost of the federal IDR process and may eventually be passed on to patients, which is not the intent of the law,” the two wrote Jan. 16. “An efficient federal IDR process is essential to maintaining the success of the law,” they added later.