IRS broke the law more than 40K times by sharing addresses with ICE, judge says

Sharing some taxpayer information with Immigration and Customs Enforcement amounted to the IRS breaking federal law “approximately 42,695 times,” a federal judge said in a court filing Thursday.

That 42,695 figure refers to the number of taxpayer addresses the IRS disclosed to ICE through the process of Taxpayer Identification Number (TIN) Matching, Judge Colleen Kollar-Kotelly of the U.S. District Court for the District of Columbia wrote in her opinion.

ICE last summer requested from the IRS 1.28 million taxpayer records as part of a memorandum of understanding the agencies signed in April 2025. The tax agency then took ICE’s datafile — which included first names, last names, addresses, and final removal order data — and used a computer script to see if it matched agency records.

According to a court filing earlier this month from Dottie A. Romo, the IRS’s chief risk and control officer, the agency followed “procedures designed to ensure compliance with Section 6103 of the Tax Code and the MOU” — but later learned that it “may have supplied last known addresses to ICE” in cases where the data provided by ICE was “either incomplete or insufficiently populated.”

Kollar-Kotelly noted in her opinion that Romo’s declaration “reaffirms” that the IRS failed to “confirm that ICE provided the ‘address of the taxpayer’ before disclosing last known addresses to ICE.” The verification process was flawed, the judge continued, when the tax agency pursued TIN Matching without checking the ICE-supplied addresses “beyond its initial automated check for a zip code proxy.”

Out of the 1.28 million requested records, the IRS matched 47,289 taxpayer addresses and shared those with ICE. Just 9.7% (4,594) were properly matched by address, while the other 90.3% (42,695) were done through TIN Matching, according to the new court document.

“Accordingly, the IRS violated the [Internal Revenue Code] approximately 42,695 times by disclosing last known taxpayer addresses to ICE through TIN Matching without confirming that ICE’s request set forth the ‘address of the taxpayer with respect to whom the requested return information relate[d],’” Kollar-Kotelly wrote. 

The Washington Post was first to report on Kollar-Kotelly’s filing, which was issued as a federal appeals court considers the judge’s November ruling to block the IRS from sharing addresses with ICE. 

Earlier this week, a federal appeals court in a separate case regarding the IRS-ICE agreement ruled that the tax agency could continue sharing data with the Department of Homeland Security component. A different federal judge, meanwhile, ruled earlier this month that ICE could no longer use data acquired from the IRS in its enforcement efforts, citing the “high potential for misidentification” and improper agency rulemaking.