Congress may have protected patients from certain surprise medical bills, but it didn't end the fight between insurers and providers over out-of-network bills — and providers are winning.

Why it matters: The dispute resolution process that lawmakers created to settle billing disputes may be so skewed in favor of providers that it encourages them — and third-party vendors — to view arbitration as a lucrative option.

• Providers, for their part, are complaining that insurers aren't promptly paying up after they lose.

Catch up quick: The No Surprises Act was signed into law more than five years ago to address the medical bills patients received when they unintentionally received care from an out-of-network provider.

• The practice of "balance billing" was not only hard on patients, it also had an inflationary effect on in-network prices paid to the types of providers likely to generate balance bills, some experts said.
• A classic scenario went like this: A patient brought to the nearest hospital during an emergency was seen by an emergency room physician who didn't contract with their insurer. When the patient's insurer refused to cover what was charged, the doctor billed the patient.
• That gave ER doctors and other providers an upper hand in contract negotiations, critics said, because they could argue for higher payment rates as an alternative to balance billing.

Congress successfully took patients out of the middle of such billing disputes. But the arbitration system it set up for when insurers and providers couldn't agree on a payment rate isn't exactly working out.

• "Find me one congressional negotiator who intended for this law to increase costs," said Adam Buckalew, a former congressional aide who helped write the law.
• "One fact can't be ignored: The median in-network payment was the driving force behind all four committee scores. Protect patients. Lower costs. Increase network participation," he said.

The bottom line: CMS data tells a clear story: A lot of bills are being taken to arbitration, where the provider is very likely to win.

• And the winning payment bid is extremely likely to be higher than the benchmark rate designed to reflect market prices.

The other side: Winning really only matters if you collect a payment, and providers say that isn't always happening.

• "It is our understanding that many physicians are not receiving payment from health plans within the statutory 30-day time period following an IDR decision in their favor, and in fact, many physicians continue to report receiving no payment at all," the American Medical Association wrote in a letter to Congress last year.
• Providers have also questioned the accuracy of the benchmark rate.

More than 5 million disputes have been initiated since April 2022, according to CMS data last updated at the end of January. That's vastly more than the authors of the law ever envisioned.

• Nearly 3.7 million of those have ended in a payment determination, and another 900,000 were deemed ineligible for the process.

Zoom in: In the first half of 2025 — the time period for which the most recent granular CMS data is available — nearly 1.2 million disputes over payment were initiated.

• Of those, only 131 were initiated by insurers.

Of the more than 1 million resolved disputes that resulted in payment determinations, providers, facilities or air ambulances won 88% of the time during the same time period.

• And also in 88% of the cases, the offer that won was higher than the benchmark designed to represent the median in-network price for that particular service.
• In fact, the winning offers are often multiple times the value of the benchmark rate, per the data.

Based on the number of bills being disputed, you'd be forgiven for thinking this fight is affecting providers and insurers all over the country. Truth is, a handful are extremely overrepresented in the data.

State of play: More than half of the payment disputes in the first half of 2025 were initiated against just three insurers: UnitedHealthcare, Blue Cross Blue Shield of Texas and Aetna, according to an analysis published yesterday in Health Affairs.

• On the flip side, four provider groups or provider representatives — HaloMD, TeamHealth, Radiology Partners and SCP Health — initiated more than half of the total disputes.
• Plans challenged 40% of the cases as ineligible, and arbitrators ended up deeming 17% ineligible.

The intrigue: The top initiators are also winning significantly large payment rates, per the Health Affairs analysis.

• During the first half of 2025, Radiology Partners' awards were around 600% of the benchmark rate designed to reflect market prices, SCP Health won awards around 370% of the benchmark, and TeamHealth won rates that were a median of 277% of the benchmark.
• HaloMD — which Stat News wrote a must-read piece about this week — won payments of 920% and 835% of benchmark rates in the first two quarters of 2025, respectively.
• Assuming the benchmark used is accurate, that means "certain provider groups are receiving three to nine times in-network rates," the authors write.

What we're watching: This has spawned several court cases, with plans increasingly suing providers that are active in the arbitration process.

• And providers have started to sue plans for payment, though courts have consistently "held that providers do not have such a right, including to enforce [arbitration] awards," per Health Affairs.