Obamacare Has Health Insurers Worried

The messy rollout of the exchanges has made it hard for carriers to figure out what business will be like in 2014

After soaring for months, stock prices for insurers such as UnitedHealth Group and Aetna have lost altitude in recent weeks. Although the rollout of the glitch-plagued federal health-insurance website is partly to blame, it’s what lies ahead that has investors concerned. “There’s a whole host of operational questions about 2014,” says Thomas Carroll, a health-care analyst at Stifel Nicolaus.