Jan. 29 (Bloomberg) –WellPoint Inc., the second-biggest medical carrier, added 500,000 new members since Obamacare enrollment began and said the system's early stumbles haven't dimmed profit estimates, boosting the company's shares.

While the new members tend to be older and sicker than current enrollees, WellPoint priced its plans accordingly and isn't backing off of projected profit margins, Chief Executive Officer Joseph Swedish told analysts on a conference call today. The prognosis helped WellPoint shares overcome a 68 percent decline in fourth-quarter net income.

Three million Americans had signed up for insurance under the Patient Protection and Affordable Care Act as of last week, overcoming technical disruptions and delays that hamstrung enrollment in October and November. Only about a quarter were younger than 35, raising concern that medical costs for the new coverage would be unsustainable.