CHICAGO (AP) — A struggling Illinois health insurance co-op is suing the federal government, claiming it’s being shortchanged of $72.8 million in promised payments under the Affordable Care Act.

Chicago-based Land of Lincoln Health filed the lawsuit Thursday in the U.S. Court of Federal Claims in Washington, D.C.

At least four other insurers previously filed similar lawsuits over a provision in the law meant to help unprofitable insurers. The others are Health Republic Insurance Company of Oregon, Pittsburgh-based Highmark Inc., Blue Cross and Blue Shield of North Carolina and Oregon-based Moda Health.

At issue is the risk corridor program. In October, the government told insurers it would pay less than 13 cents on the dollar of the amount requested by insurers to cover losses.

U.S. Health and Human Services spokesman Aaron Albright declined to comment on pending litigation.