ObamaCare's rocky rollout will reduce first-year enrollments in the law's private coverage options by about 1 million people, congressional budget analysts said.
The Congressional Budget Office (CBO) decreased its estimate for initial sign-ups from 7 million to 6 million in a report Tuesday, citing the "technical problems" that plagued the exchanges last fall.
The estimate represents one of the first official attempts to peg the consequences of ObamaCare's troubled rollout in terms of the number of people signing up.
While acknowledging the likelihood that enrollments will initially suffer, the CBO said that ObamaCare's exchanges could make the original projection of 7 million with a strong wave of registrations before the March 31 deadline.
Analysts also predicted sharp upticks in enrollments within two years, with 22 million expected in 2016.
In the meantime, anticipated spending for subsidies on the exchanges was revised downward by $16 billion compared with the CBO's May 2013 estimate.
Tuesday's report made big news in Washington with its conclusion that the healthcare law is slowing economic growth, costing jobs and increase the budget deficit.
The CBO also threw a wrench into a Republican proposal to eliminate ObamaCare's "risk corridors," noting that this move would deprive the government of $8 billion in revenue.
The GOP had previously decried the "risk corridors" as a bailout for insurers.