Blues plans have submitted their intent to offer a national plan that would be in 31 states next year, said Alissa Fox, the association’s senior vice president for policy. Those include New Mexico, Michigan, Kansas and Arkansas, according to public filings.

Even if the Blues are approved in those states, that may leave 19 states without any national plan.

Other insurers, such as Humana, have said they will not offer multi-state plans next year. A few, such as UnitedHealth Group, have been noncommittal.

“The idea was to offer at least two options” to consumers, no matter what other insurers might be there, said Timothy S. Jost, a professor at Washington and Lee University School of Law in Lexington, Va.

In some counties or regions, especially in rural areas, such plans may be the only coverage available to people, he said.