In a complaint filed in Miami federal court, Trump, his adult sons, and his namesake company said the agencies failed to take "mandatory precautions" to prevent former IRS contractor Charles Littlejohn from leaking their tax returns to "leftist media outlets", including the New York Times and ProPublica.
The plaintiffs said they suffered "significant and irreparable harm" to their reputations and financial interests, and may seek punitive damages because the leaks were either willful or resulted from gross negligence.
Thursday's lawsuit puts Trump in the unusual position of suing government agencies that are part of the Executive Branch, which he leads.
The IRS is part of the Treasury Department. Neither agency immediately responded to requests for comment.
Scott Bessent, the Treasury Secretary and acting IRS commissioner, is not a defendant. Other plaintiffs include Donald Trump Jr., Eric Trump and the Trump Organisation.
President Trump has filed many lawsuits in his personal capacity, often for large sums and as a result of reporting by various media, since winning a second White House term in 2024.
He sued the New York Times and book publisher Penguin Random House for $US15 billion over articles and a book he said were intended to undermine his election prospects in 2024.
Trump is separately seeking $US10 billion from the Wall Street Journal over an article discussing a birthday greeting for disgraced financier Jeffrey Epstein, and $US10 billion from the BBC over its editing of a speech preceding the January 6, 2021 storming of the US Capitol.
Alejandro Brito, a Florida-based lawyer, filed or helped file all of these lawsuits, as well as the lawsuit against the IRS and Treasury Department. He did not immediately respond to a request for comment after business hours.
In Thursday's complaint, Trump and the other plaintiffs said the New York Times published at least eight articles, and ProPublica published at least 50 articles, based on Littlejohn's disclosures.
The leaks "caused plaintiffs reputational and financial harm, public embarrassment, unfairly tarnished their business reputations, portrayed them in a false light and negatively affected President Trump, and the other plaintiffs' public standing," according to the complaint.
Prosecutors charged Littlejohn in September 2023 with leaking tax records of Trump and thousands of other wealthy Americans to the media, saying he was motivated by a political agenda.
Littlejohn, 40, pleaded guilty the following month to disclosing income tax return information without authorisation, and was sentenced in January 2024 to five years in prison.
The disclosures revealed that Trump paid just $US750 in federal income taxes in 2016 and 2017.
with EFE
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