The University of Minnesota and medical residents will continue to face millions in Social Security tax payments in the wake of a U.S. Supreme Court decision Tuesday.

The Court unanimously ruled against the University and Mayo Foundation, who claimed medical residents should be exempt from Social Security taxes like other student employees.

The parties brought the case against the IRS hoping to reverse a 2005 change to Treasury Department guidelines, which labeled the residents as full-time employees who must pay the tax.

But the Supreme Court upheld the IRS rule that, although the residents’ work is part of their education, they put in more than 40 hours per week and are not like other students, the AP reports.