Officials at the Department of Health and Human Services (HHS) on Monday projected that up to 9.9 million people would be enrolled in ObamaCare in 2015, millions fewer than Congressional Budget Office (CBO) estimates.
HHS, which previously declined to project 2015 sign-ups, said that between 9 million and 9.9 million people are expected to participate in the exchanges in 2015.
The figure was less than the CBO’s projection of 13 million for 2015 enrollment, raising questions about the exchanges' performance, compared with expectations.
HHS officials described their figures as more complete than the CBO's and said the health insurance marketplaces are simply not "ramping up" at the rate the office projected.
Officials rejected the notion that the slower adoption rate could pose a problem for President Obama's signature healthcare law.
"Our charge was to make use of the available data to learn from our experiences and to build a projection from the ground up," said an HHS official, who declined to be identified on the record.
"We think the evidence points to a longer ramp-up rate than the CBO projections had, and that is based on what we've learned over the last year from looking at our own data."
The last CBO estimates were from April, not long after the close of open enrollment. The office estimated that sign-ups on the exchanges would increase steadily to hit 25 million in 2017, a figure that is widely cited as a target for ObamaCare's success.
The HHS said it's likely to take "four or five" years for the system to reach maturity, but emphasized that 9 million to 9.9 million exchange participants in 2015 will still be "important and significant."
The tension between the HHS and CBO projections is likely to draw criticism from Capitol Hill, where critics of the law are sensitive to any signs it might be encountering trouble.
The CBO conducts nonpartisan analysis of laws and legislation that is often seen as authoritative, even as it irritates partisans on both sides.
The new projections are released at a crucial time as federal health officials are preparing for the marketplaces to open for enrollment on Saturday.
The system all but failed to launch last year, a technological and political mess for the Obama administration that nonetheless seemed to lighten as more than 8 million people signed up.
The HHS said Monday that 7.1 million people remained as paying customers in the marketplaces as of last month.
Officials also said 112,000 people lost their ObamaCare coverage this year because they did not verify their eligibility based on citizenship and immigration status.
Another 120,000 households could see their costs rise on Dec. 1 because they did not provide enough income data to maintain their original premium subsidy level.