Slightly more than than 40,000 of those people had selected plans in the prior week. Those people were taking advantage of an effective weeklong waiver of the Feb. 15 sign-up deadline, which was offered to those who were in the process of applying for coverage at the time the deadline was reached.
At least another 2.8 million people had signed up for coverage sold through one of the 14 other exchanges run by individual states and the District of Columbia as of Feb. 15, bringing total Obamacare sign-ups nationally to about 11.6 million people so far. For sign-ups to be official enrollments, customers must pay their first month's premiums; there currently is no data of paid enrollments.
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"The numbers are encouraging," said Health and Human Services Secretary Sylvia Burwell during a Google Hangout chat on Wednesday. "We're pleased with those numbers and pleased that more new enrollees came in."
"But, as always, I feel we need to do more. We know that there are still uninsured," Burwell said.
About 53 percent of HealthCare.gov customers for 2015 plans, or 4.67 million, were new customers, she added. The balance were prior customers.
This year, the second season of Obamacare enrollment, was also the first time that most HealthCare.gov customers were automatically re-enrolled in their existing plans. Customers who were re-enrolled had the option of switching plans or dropping coverage altogether.
The Obama administration instituted the re-enrollment program to maintain its existing customer base, but the administration also repeatedly urged existing customers to shop around on the exchange for potentially better and less expensive coverage.
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The federal subsidies that most Obamacare customers receive to help pay their monthly plan premiums are tied to the prices of certain benchmark plans. That relationship, and the rising prices of some plans, could leave customers who didn't shop for cheaper plans receiving less in subsidies at the same time their plan prices rose, meaning they would pay more personally for the plan.
HHS revealed Wednesday that 1.96 million customers accepted automatic re-enrollment in HealthCare.gov plans.
The remaining 2.21 million existing customers actively renewed their coverage. Slightly more than 1 million of those people actively selected their existing plan, while 1.2 million of those people actively selected a new plan.
Andy Slavitt, principal deputy administrator of the Centers for Medicare and Medicaid Services, said the fact that more than half of the existing customers actively selected a plan for 2015 was an encouraging sign.
"Based on my experience looking at enrollment trends with employer-sponsored coverage and Medicare, it is clear that Marketplace customers are more active, engaged and eager to shop for the coverage that's right for them," Slavitt said, using the term "marketplace" to refer to the federal exchange.