Aetna Inc Chief Executive Mark Bertolini on Wednesday said the individual Obamacare exchanges are in a "death spiral" where rising premiums push out healthy customers and leave only the sickest customers behind, which then drives up premium rates further.

Bertolini was speaking at a Wall Street Journal conference one day after it and Humana Inc. walked away from their merger because the government blocked it on antitrust grounds.

He said that early signs from 2017 enrollment in individual plans created under former President Barack Obama's national healthcare law, often called Obamacare, showed signs of an unbalanced pool of healthy and sick customers.

This article was provided by Reuters.