Note: This Expert Column was updated on April 17 to reflect a new ruling by a federal district court in Florida, Aetna et al. v. Radiology Partners et al., on April 16.
The No Surprises Act (NSA) was signed into law by President Trump in 2020 and has protected millions of consumers from some of the most pervasive types of surprise out-of-network bills. But implementation of the NSA’s independent dispute resolution (IDR) process — the mechanism put in place by Congress for health care providers and payers to resolve disputes over out-of-network rates — has been plagued by high volume, high costs, and persistent litigation that could undermine the savings expected when Congress enacted the NSA.
Even before the law went into effect in 2022, providers filed lawsuits challenging the NSA and its implementing regulations. This initial wave of litigation has largely been resolved, with one exception where we are waiting on a decision from the full panel of judges on the Fifth Circuit Court of Appeals. But those cases have been replaced by a new wave of lawsuits over the NSA.
Most recently, stakeholders have begun suing each other over IDR awards and conduct during the IDR process. Health care providers are suing payers and IDR entities to overturn or obtain payment for IDR awards. Meanwhile, payers are suing health care providers and IDR middlemen to overturn IDR awards and try to stop these entities from allegedly abusing the IDR system.
In what appear to be the first two decisions in NSA lawsuits by insurers, two federal district courts—one in California and one in Florida—have dismissed insurers’ claims. On April 9, a federal district court in California dismissed Anthem’s claims against HaloMD — a prominent IDR middleman that specializes in arbitration — and its affiliates. On April 16, a federal district court in Florida dismissed Aetna’s claims against Radiology Partners — a private equity-backed group of radiology practices — and its affiliates. This Expert Column discusses the recent court decisions in Anthem et al. v. HaloMD et al. and Aetna et al. v. Radiology Partners et al., what they might mean for future litigation, and other recent developments in lawsuits over the IDR process.
Brief Background
The NSA uses “baseball-style” arbitration to resolve payment disputes between payers and out-of-network providers. Either party can initiate an IDR dispute through the IDR portal. During the submission process, the submitting party must make certain attestations, including that the dispute is eligible for IDR under the NSA. From there, each party offers a payment amount, and the IDR entity selects one amount or the other.
In laying out the requirements for the IDR process, Congress specified that an IDR entity’s decision is binding on the parties and not subject to judicial review except in limited circumstances. Specifically, an IDR entity’s decision is binding unless there is “a fraudulent claim or evidence of misrepresentation of facts presented to the IDR entity involved regarding such claim.” And an IDR entity’s determination is not subject to judicial review except under four narrow circumstances incorporated from the Federal Arbitration Act (FAA). Under this part of the FAA, a court may vacate an arbitration award that stemmed from corruption, fraud, or undue means — or where the arbitrator engaged in misconduct or corruption, or exceeded their powers.
Although both parties can use the IDR process, health care providers are initiating and winning IDR disputes at exceptionally high rates. During the first six months of 2025, providers and facilities initiated 99.9% of all disputes. Most of these disputes were initiated by four provider groups and provider representatives: HaloMD, Team Health, Radiology Partners, and SCP Health. HaloMD initiated the most disputes, accounting for 17% of all disputes in the first quarter of 2025 and 22% of all disputes in the second quarter of 2025. During this time period, providers also won 88% of disputes — the highest provider win rate to date. Radiology Partners prevailed most often, winning favorable IDR awards in 92% and 95% of its cases in the first two quarters of 2025, respectively. HaloMD won slightly less often, but still prevailed in 87% and 82% of its disputes in the first two quarters of 2025, respectively.
As previously discussed, these lopsided IDR results are contributing to litigation by both providers and payers. However, both sets of stakeholders have found themselves without a private right of action to sue. So far, courts have largely concluded that the NSA bars these parties from challenging or otherwise suing over IDR awards and the IDR process.
Health Care Providers Sue Payers
Providers initiated the first round of stakeholder lawsuits by suing payers and IDR entities over allegedly improper IDR determinations and to obtain payment of IDR awards. These lawsuits are described in more detail here, and we are tracking several ongoing lawsuits here. In addition to the cases we are formally tracking, we are aware of hundreds of lawsuits in which providers are suing payers over unpaid IDR awards — sometimes for millions of dollars. As explained above, providers can seek judicial review of IDR determinations only under limited circumstances. If a provider’s claim does not meet these limited circumstances, the NSA does not authorize an explicit private right of action.
To date, courts that have addressed this question — including the Fifth Circuit and the Eleventh Circuit — have largely held that providers’ allegations do not qualify for judicial review under the FAA and that the providers do not otherwise have a private right of action under the NSA to sue for the enforcement of IDR awards. As a result, courts are barred from overturning, vacating, or enforcing IDR awards. Many courts are continuing to rule this way. As recently as April 2026, a federal district court in Pennsylvania held that the NSA does not contain a private right of action and dismissed a lawsuit over unpaid IDR awards filed by Advanced Vascular Associates against Horizon Blue Cross Blue Shield of New Jersey.
However, not all courts have reached this conclusion. To our knowledge, only two courts have allowed providers’ claims to proceed. In March 2026, a federal district court in Maryland held that the NSA “impliedly authorizes a very narrow private right of action” to ensure that IDR awards are paid. Courts can, the judge noted, “convert a ‘binding’ IDR determination to a judgment if the obligated party does not comply with its statutory payment obligation.” This decision followed a May 2025 ruling by a federal district court in Connecticut, which held that the NSA includes an implied private right of action that allows parties to ask a court to enforce IDR awards. Both cases are ongoing.
With hundreds of lawsuits filed by providers, more decisions — followed by appeals of those decisions — are expected. In New Jersey alone, providers have filed hundreds of lawsuits to try to enforce IDR awards against various insurers. There have already been at least three decisions where the court found no private right of action and dismissed the providers’ NSA claims. These providers responded by bringing the same claims but under different legal theories, such as for unjust enrichment or violations of the Employee Retirement Income Security Act (ERISA). This led the chief judge of the federal district court of New Jersey to stay and administratively terminate pending NSA cases until the court issues a decision in a “lead case” filed by Rowe Plastic Surgery of New Jersey against Aetna.
As noted above, the Fifth and Eleventh Circuits have already rejected a private right of action for providers. And the Second Circuit will hear argument in a related case, filed by East Coast Advanced Plastic Surgery against Cigna, in June 2026. These questions could eventually reach the Supreme Court, but the Court has shown little appetite for these cases thus far. In January 2026, the Supreme Court declined to hear Guardian Flight’s appeal of a Fifth Circuit decision that found that the air ambulance company could not sue the Health Care Service Corporation over unpaid IDR awards.
Payers Sue Health Care Providers
At the same time, payers have turned to the courts to sue health care providers and IDR middlemen, citing allegations about the volume of ineligible disputes and other abusive IDR practices. To our knowledge, Aetna’s lawsuit against Radiology Partners — filed in December 2024 — was the first of these lawsuits. And more quickly followed. As of this writing, we are formally tracking 13 such cases but are aware of multiple others.
Many of these lawsuits have been filed against the entities that are responsible for initiating the majority of IDR disputes, including HaloMD and Radiology Partners. In addition to the lawsuits against HaloMD and Radiology Partners by Anthem and Aetna, respectively, there are pending lawsuits against HaloMD in Georgia, Ohio, and Texas, as well as at least one lawsuit against SCP Health in Virginia. Over the past few months, payers have sued providers and IDR middlemen in at least Arizona, Hawaii, Kentucky, New Jersey, and Pennsylvania.
Payers generally assert that providers and IDR middlemen have “weaponized” the federal IDR system by intentionally flooding it with ineligible disputes in an attempt to overwhelm the system, obtain default awards, and maximize reimbursement. The plans raise a variety of claims but generally allege that this conduct amounts to fraud, misrepresentation, and violations of state and federal laws, including the federal Racketeer Influenced and Corrupt Organizations Act and ERISA.
Just like the providers, payers must overcome the NSA’s general bar on judicial review to seek relief from the courts. And, to our knowledge, no court had ruled on an insurer’s ability to challenge an IDR award under the NSA — at least not until the recent court decisions in Anthem et al. v. HaloMD et al. and Aetna et al. v. Radiology Partners et al.
Two Courts Conclude that Insurers Cannot Challenge IDR Awards and Conduct
Within the span of one week, federal district courts on opposite sides of the country rejected insurers’ attempts to sue IDR middlemen and health care providers over alleged abuses of the IDR process. As noted above, Aetna had sued Radiology Partners and its affiliates in Florida, while Anthem had sued HaloMD and its affiliates in California. Both courts dismissed the insurers’ claims after finding that the NSA bars judicial review. Below, we describe the claims made and the courts’ conclusions in each case.
In July 2025, Anthem sued HaloMD and its affiliates, alleging that more than half (55%) of HaloMD’s dispute submissions were ineligible for the IDR process and resulted in millions of dollars in improper payments to providers. HaloMD and the other defendants were able to file ineligible claims, Anthem alleges, by intentionally ignoring IDR system guardrails intended to prevent such claims from being submitted. Anthem’s filings detail the IDR portal submission process to allege that HaloMD knowingly made deliberate misrepresentations when submitting ineligible disputes through the IDR system. Anthem asserted that this conduct violated various federal and state laws and that various IDR determinations should be vacated. These claims, Anthem argued, were reviewable under the FAA because HaloMD and the other defendants used fraud and undue means to secure these IDR awards — and because each IDR entity exceeded its authority by issuing IDR awards for ineligible disputes.
On April 9, 2026, a federal district court in California dismissed Anthem’s claims. Citing Ninth Circuit caselaw, the court found that Anthem failed to show that the narrow exceptions for review under the FAA — i.e., that the IDR determinations were procured by fraud or undue means, or by the IDR entity exceeding their authority — were met. As a result, the NSA bars the court’s review of Anthem’s claims.
In reaching this conclusion, the court emphasized that Anthem had the ability to address dispute eligibility within the IDR process. IDR entities are responsible for determining whether various disputes are eligible for IDR, and the court pointed to Anthem’s own assertion that the IDR entities have, in some circumstances, found IDR disputes to be ineligible. Even if Anthem disagrees with an IDR entity’s determinations, the insurer had an opportunity to dispute the issue with the IDR entity. Anthem, the court noted, “pleaded itself out of court … because the ‘fraud’ was known during the IDR [process] and disclosed to the IDR [entity].” Further, Anthem could not show that the IDR awards were procured through undue means. Why? Because IDR entities were merely using the fee structure and incentives that Congress created under the NSA. The incentives associated with IDR fees, the court noted, are not akin to bad faith or bribery.
In December 2024, Aetna alleged that Radiology Partners initiated tens of thousands of IDR disputes, including on behalf of in-network medical practices that are ineligible for IDR, as a way to overwhelm the IDR process and secure higher payments. Aetna argued that Radiology Partners acted fraudulently, violated ERISA, and violated contract and consumer protection laws, among other claims. This activity, the payer argued, qualified for judicial review because it falls under the narrow statutory exceptions included in the NSA. Aetna asked the court to vacate fraudulently obtained IDR awards, enjoin similar practices going forward, and award damages. In August 2025, the district court allowed Aetna to amend its complaint while denying various motions from Radiology Partners as moot.
Aetna’s amended complaint, filed in October 2025, explained that it had terminated its prior contract with Mori, Bean and Brooks, Inc. (MBB) — one of the at least nine practices acquired by Radiology Partners — for allegedly “funneling” non-MBB provider claims for in-network reimbursement through MBB. Radiology Partners allegedly did this in order to take advantage of MBB’s “lucrative” in-network rates with Aetna. After Aetna terminated MBB’s contract, Radiology Partners then initiated IDR disputes under MBB’s name for out-of-network care. Radiology Partners allegedly did so even though the care at issue was provided by other (i.e., non-MBB) radiology practices who remained in network with, and thus had an active contract with, Aetna. As a result, Aetna paid funds to MBB for in-network care that is not subject to IDR under the NSA and that were not provided by MBB.
On April 16, 2026 — one week after the California court decision — a federal district court in Florida dismissed Aetna’s claims against Radiology Partners. Although it reached the same conclusion as the California court, the Florida court acknowledged that Aetna sufficiently alleged fraudulent claims by Radiology Partners. The resulting IDR awards, the court noted, injured Aetna through IDR fees and higher reimbursement payments. Even so, the court found that the FAA’s narrow exceptions for judicial review of arbitration determinations were not met because Aetna (1) knew about this fraudulent behavior and (2) failed to raise it in the IDR dispute process. Indeed, Aetna’s reasoning for terminating its contract with MBB, which was articulated in its amended complaint, proved to be “fatal to Aetna’s position.” Finally, Aetna’s other claims — such as its claims under state law — were also dismissed because they were premised on the same facts as Aetna’s fraud claim and thus preempted by the NSA and FAA.
What Happens Next?
Anthem quickly appealed the district court’s ruling to the Ninth Circuit, where briefing will proceed. Aetna may very well do the same. The appeals processes in both cases will be closely watched by federal officials, industry stakeholders, and other courts. Indeed, Anthem’s lawsuit generated interest from the California Medical Association, which filed an amicus brief in support of HaloMD, as well as AHIP and a coalition of employer groups led by the American Benefits Council, which filed amicus briefs in support of Anthem.
The district courts’ rulings in Anthem et al. v. HaloMD et al. and Aetna et al. v. Radiology Partners et al. appear to be the first two decisions in a case where a payer has sued a health care provider or IDR middleman over IDR activity. Just as courts have largely ruled that providers do not have a private right of action to use the courts to enforce IDR awards, these courts reached similar conclusions when Anthem and Aetna sought to overturn IDR awards and challenge IDR conduct.
But this is not the end of the story. In addition to monitoring appeals in these cases, we are still awaiting decisions in several other payer lawsuits, including three other cases against HaloMD that were filed in three different states. Several of these cases (as well as other pending cases in which payers make similar arguments) are fully briefed, and we could see new decisions at any time. Those courts could reach a different conclusion than the district courts in California and Florida, and those decisions are likely to be appealed. Over time, we may see different rulings and outcomes across appellate courts. As with the provider lawsuits noted above, the scope of the NSA’s bar on judicial review may ultimately need to be taken up by the Supreme Court, especially if there are dueling court rulings that result in a circuit split.
Meanwhile, beyond the courtroom, the Trump administration is poised to make its own changes to the IDR system. Federal officials are currently reviewing a draft final rule that would address stakeholder concerns related to the IDR process. The scope of the final rule is not known, but the Biden-era proposed rule included new restrictions on batched disputes and an overhaul of the eligibility review process. These changes could help address some of the concerns reflected in payer lawsuits about the high volume of disputes and the submission of ineligible cases, in particular.
DISCLAIMER: The views and opinions expressed in this piece are those of the authors and do not reflect the views of the O’Neill Institute.
