Aetna announced Thursday that this would be the last year it participates on the Obamacare exchange in Iowa, where it is the dominant insurer. The move comes days after Wellmark Blue Cross Blue Shield announced it was leaving the state's market after this year. Both insurers also will stop selling individual market policies outside of the exchange in Iowa.

Aetna and Wellmark are the latest carriers to exit Obamacare for 2018. They cited financial risk and uncertainty as the reasons behind their decisions.