A court in Washington, D.C., has determined that the Trump administration breached IRS regulations by sharing confidential taxpayer data with Immigration and Customs Enforcement (ICE).

In February 2025, the Center for Taxpayer Rights, a nonprofit organization, along with two unions, initiated a lawsuit following a campaign by the Department of Government Efficiency (DOGE). This campaign sought access to sensitive information systems and aimed to restructure various federal agencies.

As a result of these legal challenges, the Trump administration has significantly reduced the involvement of DOGE personnel in administrative agencies. The lawsuit is being handled on two fronts, as U.S. District Judge Colleen Kollar-Kotelly, appointed by Bill Clinton, had previously halted the extensive data-sharing arrangement between ICE and DOGE in late November 2025.

The federal government is contesting the district court’s stay, pending review by the U.S. Court of Appeals for the D.C. Circuit. Meanwhile, the district court continues to examine the fundamental issues of the case.

During the appeal process, the district court cannot grant further relief. However, on Thursday, the judge issued a provisional ruling, indicating that the IRS violations identified could prove significant in future proceedings.

In a 13-page memorandum opinion and order, Judge Kollar-Kotelly remarked that the IRS likely committed multiple violations, which will be important for the ongoing case record.

Under the relevant portion of the Internal Revenue Code (IRC), the IRS must ensure an agency’s request for tax return data contains a certain combination of information — including each taxpayer’s name and address. That process was not followed by ICE.

Through over 47,000 such requests, ICE failed to meet the requirements the overwhelming majority of the time, the court noted. Instead, ICE used taxpayer identification numbers (TIN) along with names. Still, the IRS sent the requested data along anyway.

“Accordingly, the IRS violated the IRC 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 explained.

The judge also found that many times when ICE did not include addresses in its requests, the immigration agency submitted forms where the necessary information was “either incomplete or insufficient,” according to a declaration filed by a risk and control officer with the IRS. In those cases, the IRS actually provided taxpayer addresses to ICE, the court explained.

The judge details several such deficiencies, at length:

The IRS, for example, disclosed to ICE the last known addresses for taxpayers in situations where ICE supplied an “address of the taxpayer” in its request that contained “language indicating that the address was not complete, such as ‘Failed to Provide,’ ‘Unknown Address,’ or ‘NA NA.’” The IRS also disclosed to ICE the last known addresses of taxpayers where the ICE-supplied address was missing essential information, such as “a street name or street number.” Still more, the IRS disclosed to ICE the last known addresses of taxpayers where the ICE-supplied address “referred to, described, or named specific locations”—examples of which are “jails, detention facilities, or prisons.”

“In other words, the IRS not only failed to ensure that ICE’s request for confidential taxpayer address information met the statutory requirements, but this failure led the IRS to disclose confidential taxpayer addresses to ICE in situations where ICE’s request for that information was patently deficient,” the order goes on.

The judge goes on to offer a hypothetical in an attempt to explain the extent of the violations that occurred with the data — highlighting the lack of safeguards used by the IRS when processing ICE’s requests.

“For instance, ICE could have submitted a request with an ‘address’ like, ‘Don’t Care 12345,’ or, ‘00000,’ and still received a taxpayer’s address through the IRS’s TIN Matching process,” the opinion continues.

Since the information the opinion relies on was provided by the IRS itself, the plaintiffs say the basic admissions of fault necessitate discovery. And they want their discovery requests expedited.

The Trump administration, in turn, argued that discovery should not be available because the case was brought under the Administrative Procedure Act (APA), which typically relies on a discovery-like administrative record. Here, the court more or less split the difference.

“[T]he Court determines that Plaintiffs’ request for discovery to supplement the record on appeal ‘raises a substantial issue,’” the opinion goes on. “Although discovery is generally not permitted in APA cases, Plaintiffs have raised a genuine question as to whether an exception to this general rule should apply.”

Still, due to the procedural nature of the case — in which the judge largely lacks jurisdiction on key issues — Kollar-Kotelly punted.

While terming discovery a “substantial issue,” the court said it would prefer to formally rule on the matter “only if the court of appeals agrees that it would be useful to decide before” the appeal is ruled on.