The figure represents the worst case scenario, CBO says, and the law could just as well increasing employer coverage by 3 million lives in 2019. The best estimate, subject to a “tremendous amount of uncertainty,” is that about 3 million to 5 million fewer people will obtain coverage through their employer each year from 2019 through 2022.

The new report adds more detail to this week’s update of the law’s coverage provisions, which CBO released Tuesday. Compared to a year ago, the law is now anticipated to cover two million fewer people but cost $50 billion less over 10 years, after factoring penalties paid by individuals and businesses that don’t get or provide healthcare coverage.

Republicans immediately pounced after the new numbers came out because they appear to violate Obama’s pledge that people who like their health plans will be able to keep them. Last year, CBO’s best estimate was that only one million people would lose employer-sponsored coverage.