U.S. health insurers would lose nearly a trillion dollars in new revenue between 2013 and 2020 if the U.S. Supreme Court strikes down the federal health reform law, according to a study by Bloomberg Government.

According to the study, the bulk of the lost revenue — $880 billion — would come from the additional 16 million U.S. residents that the health reform law is expected to help purchase coverage on the individual market. The remaining $220 billion in lost revenue would come from new beneficiaries under the overhaul’s Medicaid expansion.

The $1 trillion figure represents about 9% of overall revenue that insurers are expected to bring in during the eight-year period. The estimated loss of revenue would be equivalent to 0.5% of the projected U.S. gross domestic product in that time period.

Bloomberg Government health analyst Matt Barry, who prepared the report, said, “It’s a confirmation of, one, how much money we’re spending as a nation on health care; and two, how much is riding on this court case and the Supreme Court’s decision.”