Two major hospital groups released a joint report Tuesday warning that if Republicans repealed the Affordable Care Act without a replacement following the model of their 2015 repeal legislation, it would have a negative financial impact on hospitals amounting to hundreds of billions of dollars over the next 10 years.

“The report finds that this would result in the largest ever cut to hospital funding, nearly 100% more than the Balanced Budget Act of 1997,” the Federation of American Hospitals said in its release announcing the report, which it conducted with the American Hospital Association.

The groups also sent joint letters to the President-elect Donald Trump and congressional leaders highlighting their findings. They said, at a baseline, hospitals would suffer $165.8 billion in losses between 2018-2026, if Obamacare is repealed without a replacement. Those losses include losses in revenue from those recently covered by the ACA—both on the insurance exchanges and through Medicaid.

The hospital groups said they would suffer another $289.5 billion in losses if Obamacare was repealed but the cuts that the Affordable Care Act imposed on Medicare and Medicaid Disproportionate Share Hospital payments remained. Those payments were reduced under the Affordable Care Act on the assumption that the increases in coverage the law would bring would reduce cost of uncompensated care that hospitals offered to uninsured people in the pre-ACA world.

“Losses of this magnitude cannot be sustained and will adversely impact patients’ access to care, decimate hospitals’ and health systems’ ability to provide services, weaken local economies that hospitals help sustain and grow, and result in massive job losses,” said the letter, which was signed by American Hospital Association President Richard J. Pollack and Federation of American Hospitals President Charles N. Kahn.

“As you know, hospitals are often the largest employer in many communities, and more than half of a hospital’s budget is devoted to supporting the salaries and benefits of caregivers who provide 24/7 coverage, which cannot be replaced,” the letter added.

The letter noted that earlier Republican plans to replace Obamacare, like the plan offered by Rep. Tom Price (R-GA), who Trump recently nominated as his Health and Human Services secretary, included measures that took these concerns about the payments into account. The repeal measure Congress voted on last year and now is floating as its model for next year left the cuts to the payments in place, however.

“It stands to reason that, if the funding and cost of the ACA is repealed, all sources of funding for that legislation, including cuts to payments for hospital services, should be rolled back as well,” the letter said.

Read the letter below: