The IRS is expected to lose $12 billion in revenue for the remainder of the fiscal year ending Sept. 30, according to a report out Tuesday by the Yale Budget Lab. The group estimates unauthorized workers paid about $66 billion in federal taxes in fiscal year 2023, with about two-thirds of that coming from payroll levies.

The Treasury Department—which oversees the IRS—earlier this week reached a deal with the Department of Homeland Security to share taxpayer information in response to law enforcement requests related to migration. While federal officials say the agreement includes safeguards and applies only to criminal matters, it reverses longstanding IRS privacy policies.

The report underscores the role undocumented workers play in paying into Social Security and Medicare benefit programs that they can’t draw from in retirement because of their immigration status. 

“The IRS has historically made clear to the undocumented immigrant population that their tax information is confidential and would not be used in such ways,” the report said. Tax compliance could fall among that group “if they become concerned that filing taxes could expose their personal contact information to law enforcement and be used to facilitate their deportation.”

President Donald Trump has enlisted the IRS and other government agencies in his efforts to crack down on undocumented immigration. He’s vowed to carry out the largest mass deportation campaign in U.S. history, and so far is ramping up raids and encouraging undocumented immigrants to “self-deport.”

The report notes that there’s “considerable uncertainty” around the estimates, as they will depend strongly on the behaviors of undocumented immigrants and their employers. The 10-year loss in revenue could be as low as $147 billion and as high as $479 billion, according to the Budget Lab.