A group of Democratic senators is urging federal law enforcement officials to investigate and prosecute some of the most popular online tax filing companies for allegedly sharing millions of taxpayers’ financial data with Meta and Google. 

On Tuesday, Sens. Elizabeth Warren (D-MA), Bernie Sanders (I-VT), and others asked the Justice Department, Federal Trade Commission, Treasury Department, and the IRS to investigate whether TaxSlayer, H&R Block, and TaxAct violated taxpayer privacy laws by sharing sensitive user information with the two tech firms.

Senators also released their own report Wednesday detailing the accusations, first raised by The Markup last November. The report alleges that for years, tax preparation companies infused their products with Meta and Google tracking pixels that revealed identifying information — like a user’s full name, address, and date of birth. The senators also suggest that some of the information provided, like the forms a user accessed, could be used to show “whether taxpayers were eligible for certain deductions or exemptions.” 

The senators claim that the companies did not receive user consent to share this information, which could violate laws banning tax preparers from sharing tax return information with third parties, especially since much of this data could be used for advertising purposes. 

“The findings of this report reveal a shocking breach of taxpayer privacy by tax prep companies and by Big Tech firms that appeared to violate taxpayers’ rights and may have violated taxpayer privacy law,” the senators said in their Tuesday letter. 

TaxSlayer, H&R Block, and TaxAct all confirmed that they shared “extensive taxpayer data” through Meta’s pixel in the senators’ report. After The Markup published its November findings, each of the companies said they had “removed or disabled” it from their websites.