Atlanta's health insurance market continues to be one of the most competitive in the country, and certainly in the South. And as major regional employers like Delta Airlines talk of a potential merger and exit from the market, the competitive focus is shifting to the small-group segment in what is still a fast-growing urban center. Meanwhile, CIGNA HealthCare's purchase of Great-West's health insurance business improves its footprint in the region, and may signal a push into the small-group segment.