So few insurers offer plans on some of the new government health insurance exchanges that consumers in those states may pay too much or face large rate increases later, insurance experts say. An average of eight insurers compete for business in 36 states that had exchanges run or supported by the federal government last month, the Department of Health and Human Services says. (Idaho has since started its own exchange.) But just because an insurer sells in a state, it doesn't mean it sells in every area of a state so many residents have far fewer options.