Roughly 6.4 million consumers signed up for Obamacare insurance on Healthcare.gov from Nov. 1 to Dec. 19 indicating "clear demand for quality, affordable coverage," the U.S. government said on Wednesday.
The number of people signing up for Jan. 1, 2017 coverage during this period represents an increase of 400,000 compared with the same period a year ago, the government said.
Total plan selections through the extended deadline of Dec. 19 include 2.05 million new consumers and 4.31 million returning consumers actively renewing their coverage.
HealthCare.gov sells plans for 39 states while the other states run their own exchanges.
Health and Human Services Secretary Sylvia Burwell told reporters on a conference call that the government's previous enrollment projection for 2017 "is one we continue to feel comfortable with."
In October the government said it expects 1 million more people will sign up for health insurance on the exchanges than in 2016. The exchanges, established under President Barack Obama's Affordable Care Act, allows consumers to shop for individual health insurance and receive income-based subsidies.
The government at that time said it expects 13.8 million people to sign up for 2017 coverage compared with 12.7 million in 2016.
Dec. 15, the original deadline for Jan. 1, 2017 coverage, was the biggest sign-up day since the plans went on sale in 2014, with 670,000 plan selections, up from last year's Dec. 15 figure of 600,000. The government said it extended the enrollment period by two business days to meet high demand.
In October the government said benchmark 2017 Healthcare.gov premiums will rise 25 percent compared with 2016. The average monthly premium for the benchmark plan will rise to $302 from $242 in 2016.
Several large insurers including UnitedHealth Group Inc and Aetna Inc have withdrawn from the exchanges for 2017, saying they are losing too much money.
The government said it provides income-based subsidies to about 85 percent of people enrolled and that 72 percent of consumers on Healthcare.gov can find plans with premiums of less than $75 a month.
President-elect Donald Trump has pledged to overturn the Affordable Care Act.