Extending the enrollment period would have a “destabilizing effect on insurance markets,” said Robert Zirkelbach, a spokesman for the Washington-based lobbyist group American’s Health Insurance Plans. Allowing younger, healthy Americans to sign up later, as they probably would, means less revenue for insurers counting on those premiums to help defray the cost of sicker customers, threatening industry profits.

“If you can enroll at any point in the year, then you can just wait until you get sick,” Brian Wright, an analyst with Monness Crespi Hardt in New York, said in a telephone interview. “This isn’t the industry crying foul and exaggerating the issue, this is actually one of those issues where there is a well-grounded reason for the concerns.”…

A later deadline would stretch insurers past the time when by law they must set rates for 2015. If insurers only have information from sicker, costlier patients in hand by the time they have to start reporting premiums to the federal government, it may force them to boost premium costs for the next year ahead, Zirkelbach said…

Aetna Inc. (AET) Chief Executive Officer Mark Bertolini said yesterday on a call with analysts that he is concerned the flaws with healthcare.gov will lead to an extension of the enrollment deadline.