Health Care Service Corp. has acquired TMG Health Inc.

Health Care Service, Chicago, is the parent of the Blue Cross and Blue Shield plans in Illinois, New Mexico, Oklahoma and Texas.

TMG Health, King of Prussia, Pa., sells administrative support services to Medicare, Medicaid and group retiree health plans with more than 2.4 million enrollees.

TMG Health will continue to operate as an independent organization, with its own board and brand identity, and Jack Tighe, the founder, will continue to be the president of the business, Health Care Service says.