"Because the return information will be disclosed to the Bureau in statistical format, specific taxpayers will not be identified, and, therefore, no taxpayers are affected by the disclosures authorized by this guidance," the agency said in its rule.
The IRS routinely shares Americans' tax information with other agencies to verify whether they qualify for social services like Medicaid, among other purposes. The agency allowed for contractor information to be shared until 2007.
The new regulation permanently codifies a temporary rule, which had been in place since 2010. That temporary regulation was in a response to a 2009 request from the Commerce Department.
Republicans have criticized the IRS's attempt to share information with other agencies as part of the Affordable Care Act.
Under the healthcare reform law, the tax agency is required to confirm people's tax return information to see if they qualify for tax credits or other assistance to buy health insurance.
GOP lawmakers have worried that Americans' personal details could be jeopardized and that they could be exposed to identity theft.