Health insurer Aetna backs off ACA expansion plans

Aetna is calling off its public insurance exchange expansion plans for next year, as it becomes the latest big insurer to cast doubt on the future of a key element of the Affordable Care Act.

The nation's third largest insurer said Tuesday that significant challenges faced by the exchanges are forcing the company to withdraw expansion plans and evaluate future participation in the 15 states where it currently sells coverage.

Several insurers say they have been struggling with higher-than-expected claims and a shortfall in government assistance, among other issues, since the exchanges opened for enrollment in the fall of 2013.

Aetna's announcement comes nearly two weeks after federal regulators said they were suing to stop the insurer's $34-billion acquisition of Medicare Advantage provider Humana.