ERISA is a federal law that requires health plans to "provide participants with plan information, including important information about plan features and funding; provides fiduciary responsibilities for those who manage and control plan assets; requires plans to establish a grievance and appeals process for participants to get benefits from their plans; and gives participants the right to sue for benefits and breaches of fiduciary duty," according to the U.S. Department of Labor.

The plaintiffs, self-funded health plan fiduciaries, claim the defendants breached their fiduciary duty under ERISA by denying the plaintiffs access to their plan claims data, failing to manage the claims "prudently, loyally, and in compliance with documents governing the plans," and partaking in "prohibited transactions relating to the management and disposition of plan assets," the complaint said.

A spokesperson for the defendants, Elevance, Anthem Health Plans Inc., Anthem Blue Cross, Empire Blue Cross Blue Shield and Empire Blue Cross, did not immediately respond for comment. No counsel has appeared yet for Anthem.

Both plaintiffs signed contracts with Anthem, and the plans pay a per-member, per-month rate for access to the network, the complaint said.

"Self-funded plans, responsible for paying all covered benefit claims from plan assets, contract with Anthem to gain access to these networks, and the discounted rates that Anthem negotiates with providers and facilities," the complaint said.

The self-funded plans in contract with Anthem do not play a role in costs paid to health care providers.

"Anthem controls all aspects of its relationships with its network providers and takes the position that information related to Anthem's provider network, provider negotiated rates, provider discounts, provider contract terms, claims processing, and claims payment, is proprietary and can be kept from plan fiduciaries even when asked by the plan fiduciaries to provide this information," the complaint said.

According to the complaint, Anthem did not allow the plaintiffs to view its claims data. When the plaintiffs began to research their claims data, based on Yale New Haven Hospital's and Hartford HealthCare facilities' negotiation rates with Anthem posted on their websites, the plaintiffs found that Anthem had been overcharging the plaintiffs, the complaint said.

"By way of example, one of the claims that was reviewed had the same billed amount— $8,698.13—as allowed amount, and that was the amount the Plan paid," the complaint said. "However, according to the negotiated rates publicly posted by Yale New Haven Hospital, the Anthem negotiated rate for this claim should have been $5,629.00, meaning the Plan paid $3,069.13 more than if it had paid Anthem's publicized negotiated rate with Yale New Haven Hospital."

The plaintiffs claim access to claims data is imperative to make sure an excess amount is not being paid.

"Plaintiffs, as the Funds' Trustees, are entitled to full access to their respective Plan's claims data," the complaint said, "to determine whether claims are being paid in accordance with Plan documents, to determine whether the fees it pays to Anthem for network access and network claims administration are reasonable, and to determine whether Anthem has used plan assets to pay itself undisclosed fees."