Major insurer Highmark Inc. is suing the federal government, arguing it is owed money under the Affordable Care Act, a move that opens yet another front in the continuing legal battles over the 2010 health law.

Highmark, the insurance arm of Pittsburgh-based nonprofit Highmark Health, said in the suit that the U.S. failed to live up to obligations to pay the insurer nearly $223 million owed under an ACA program known as “risk corridors,” which aimed to limit the financial risks borne by insurers entering the new health-law markets. The suit claims “violations of the mandatory risk-corridor payment obligations prescribed” in the health law.

The suit is likely to draw close attention because it comes from a company that continues to be a major player in the ACA health-insurance marketplaces in three states. Many other insurers also suffered major shortfalls in risk-corridor payments.

“Publicly traded companies may come under pressure from shareholders to file their own suits,” said Ana Gupte, an analyst with Leerink Partners LLC.

Highmark Health Chief Executive David Holmberg said the company had a fiduciary responsibility to its policyholders to file the suit. “All we’re asking is for the federal government to do what they promised,” he said.