In all, 543,098 people selected plans for 2016 on HealthCare.gov in the first week, which began Nov. An unknown number signed up on the other 13 Obamacare exchanges run by individual states and the District of Columbia. For coverage to go into effect — and be officially counted — customers need to make their first month's premium payment.
Open enrollment runs from Nov. 1 through Jan. 31.
U.S. Health and Human Services Secretary Sylvia Burwell has said that "we will manage" toward enrolling an estimated 10 million in Obamacare plans nationwide by the end of 2016, although she also has said that officials "estimate a final range of 9.4 million to 11.4 million people."
Such a tally would represent only modest growth from the 9.5 million people that officials expect to be enrolled in Obamacare coverage by the end of this year.
Burwell has cited the challenges presented by the remaining 10.5 million eligible uninsured people, including concerns they have about affordability of health insurance, and ignorance or confusion about federal financial assistance that is available to most of those people to help them pay for coverage. More than 8 out of every 10 customers of Obamacare exchanges qualify for such subsidies.
Under the Affordable Care Act, most Americans must have some form of health coverage or face a possible fine. The Obamacare penalty for being uninsured will rise in 2016, to the greater of $695 per adult or 2.5 percent of taxable household income.