Business owners will pay $4 billion more in taxes under President Obama’s Affordable Care Act (ACA) than the Congressional Budget Office had previously expected.

“According to the updated estimates, the amount of deficit reduction from penalty payments and other effects on tax revenues under the ACA will be $5 billion more than previously estimated,” the CBO reported today. “That change primarily effects a $4 billion increase in collections from such payments by employers, a $1 billion increase in such payments by individuals, and an increase of less than $500 million in tax revenues stemming from a small reduction in employment-based coverage, which will lead to a larger share of total compensation taking the form of taxable wages and salaries and a smaller share taking the form of nontaxable health benefits.”

In short, CBO revised the Obamacare tax burden upward by $4 billion for businesses and $1 billion to $1.5 billion for individual workers.

CBO couldn’t help but bump into Chief Justice John Roberts controversial decision uphold the individual mandate as a constitutional exercise of Congress’s taxing power. The report dubs the individual mandate a “penalty tax” — that is, “a penalty paid to the Treasury by taxpayers when they file their tax returns and enforced by the Internal Revenue Service.”